Excisional surgery versus ablative surgery for ovarian endometrioma

Abstract

Background

Endometrioma are endometriotic deposits within the ovary. Laparoscopic management of endometriomas is associated with shorter hospital stay, faster recovery, and decreased hospital costs compared with laparotomy. The previous version of this systematic review (2008), including randomised controlled trials (RCTs) of surgical interventions for endometrioma, concluded that laparoscopic cystectomy (excision) was preferable to drainage and ablation of endometrioma. We aimed to update the evidence comparing excision with drainage and ablation for improving pain and fertility‐related outcomes.

Objectives

To evaluate the safety and efficacy of laparoscopic excision (cystectomy) compared with laparoscopic drainage and ablation of endometrioma in women of reproductive age.

Search methods

We searched the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycInfo, two trials registries, grey literature sources, and conference proceedings on 19 December 2022. We also checked the reference lists of relevant papers and contacted leaders in the field of endoscopic surgery for any additional trials.

Selection criteria

Eligible studies were RCTs that compared excision with drainage and ablation of endometriomas.

Data collection and analysis

Two review authors independently assessed study eligibility, extracted data, assessed risk of bias, and applied the GRADE approach to rate the certainty of evidence.

Main results

We identified nine studies (involving 578 women) that investigated laparoscopic excision versus drainage and ablation of endometriomas measuring at least 3 cm in diameter. Participants were women of reproductive age who presented to an outpatient gynaecology clinic with pain, infertility, or both. For most outcomes, we downgraded the certainty of evidence for risk of bias due to lack of blinding and for imprecision due to low participant numbers.

At up to two years after surgery, excisional surgery compared with ablative surgery may reduce the risk of dysmenorrhoea recurrence (OR 0.25, 95% CI 0.12 to 0.52; 2 studies, 140 women; low‐certainty evidence;). Recurrence of dysmenorrhoea may occur in 49% of women after ablative surgery compared with 10% to 34% after excisional surgery.

At up to two years after surgery, excisional surgery compared with ablative surgery may reduce the risk of dyspareunia recurrence (OR 0.09, 95% CI 0.03 to 0.22; 2 studies, 131 women; low‐certainty evidence). Recurrence of dyspareunia may occur in 58% of women after ablative surgery compared with 4% to 23% after excisional surgery.

At one year after surgery, excisional surgery may reduce the risk of endometrioma recurrence compared with ablative surgery (OR 0.17, 95% CI 0.09 to 0.34; 4 studies, 264 women; low‐certainty evidence). Recurrence of endometrioma may occur in 37% of women after ablative surgery compared with 5% to 17% after excisional surgery.

At one year after surgery, excisional surgery may reduce the need for further endometrioma surgery compared with ablative surgery (OR 0.16, 95% CI 0.07 to 0.41; 2 studies, 178 women; low‐certainty evidence). Our results suggest that 32% of women require further endometrioma surgery after ablative surgery compared with 3% to 16% after excisional surgery.

There may be little or no difference between excisional surgery and ablative surgery in terms of their effect on spontaneous pregnancy during the first year after surgery (OR 1.27, 95% CI 0.33 to 4.87; 3 studies, 101 women; low‐certainty evidence).

Five studies reported that there were no conversions to laparotomy. No studies provided data about any other surgical complications or adverse effects.

Authors' conclusions

Surgical management of endometrioma with excision (cystectomy) may be more effective than drainage and ablation for reducing painful menstrual periods, pain during sexual intercourse, endometrioma recurrence, and the need for further endometrioma surgery. However, there may be little or no difference between the techniques in their effect on subsequent pregnancy rates. We found limited evidence on the safety of excisional surgery compared with ablative surgery. Future trials should recruit adequate numbers of women and measure outcomes relating to adverse events and clinical pregnancy.

Plain language summary

Which is the best surgical technique for treating endometriomas (lumps of tissue similar to the lining of the womb that grow in the ovaries)?

Key messages

• For the surgical treatment of endometriomas (deposits of tissue similar to the lining of the womb that grow on the ovaries), excision (stripping the endometriomas from the ovaries) may be better than drainage and ablation (destroying the endometriomas with an electric current or a laser) for improving painful periods, pain during sex, the risk of endometriomas returning, and the risk of needing more surgery.
• Future studies should record unwanted events and investigate whether the choice of operation affects women's chances of becoming pregnant

What are endometriomas?

Endometriosis is a condition where tissue similar to the lining of the uterus (womb) grows in other places. It can be painful and is common in women who have difficulty becoming pregnant (conceiving). Sometimes the tissue grows on the ovaries and forms a cyst (lump), called an endometrioma. Currently, surgical treatment of large and painful endometriomas usually involves stripping them away (excision) or draining and destroying them with an electric current or a laser (ablation). Most experts agree that the best way to perform both of these techniques is with keyhole surgery (laparoscopy), where the surgeon makes small cuts and uses a camera to see inside the abdomen. Many women have endometrioma surgery before starting fertility treatment or to improve their chances of conceiving naturally.

What did we want to find out?

We wanted to know whether endometrioma excision was better than drainage and ablation for improving:

• painful periods;
• pain during sex;
• the risk of unwanted events, including surgical complications and the need to switch to open surgery (laparotomy);
• the risk of endometriomas returning;
• the risk of needing more surgery;
• women's chances of conceiving naturally; and
• women's chances of conceiving with fertility treatment

What did we do?

We searched for studies that investigated excision compared with drainage and ablation of endometriomas in women having surgery to improve pain or fertility. We compared and summarised the results of the studies and rated our confidence in the evidence based on factors such as study methods and sizes.

What did we find?

We found nine studies involving 578 women aged 18 to 40 years. When we combined the results, we found that excision compared with drainage and ablation may reduce the risk of painful periods and pain during sex for up to two years after surgery. Five articles stated that there were no switches to laparotomy during the surgery, but no studies provided information about any other unwanted events. Excision compared with drainage and ablation may reduce the risk of endometriomas returning and may reduce the need for further surgery for one year after the operation. However, there may be little or no difference between the two techniques in terms of women's chances of conceiving in the year after the operation.

What are the limitations of the evidence?

We have little confidence in most of the evidence because some studies were very small, and because the women in some studies knew which type of surgery they were having.

How up to date is the evidence?

The evidence is current to December 2022.

Summary of findings

Summary of findings 1. Excisional surgery (cystectomy) compared with ablative surgery (drainage and ablation) for ovarian endometriomas.

Excisional surgery (cystectomy) compared to ablative surgery (drainage and ablation) for ovarian endometriomas
Patient or population: ovarian endometrioma Setting: tertiary hospital gynaecology outpatients department Intervention: excisional surgery (cystectomy) Comparison: ablative surgery (drainage and ablation)
Outcomes	Anticipated absolute effects* (95% CI)		Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)
	Risk with ablative surgery (drainage and ablation)	Risk with excisional surgery (cystectomy)
Recurrence of dysmenorrhoea Follow‐up: up to 2 years after surgery	Study population		OR 0.25 (0.12 to 0.52)	140 (2 RCTs)	⊕⊕⊝⊝ Lowa,b
	493 per 1000	195 per 1000 (104 to 335)
Recurrence of dyspareunia Follow‐up: up to 2 years after surgery	Study population		OR 0.09 (0.03 to 0.22)	131 (2 RCTs)	⊕⊕⊝⊝ Lowa,b
	581 per 1000	111 per 1000 (40 to 233)
Recurrence of endometrioma Follow‐up: 12 months after surgery	Study population		OR 0.17 (0.09 to 0.34)	264 (4 RCTs)	⊕⊕⊝⊝ Lowa,b
	369 per 1000	91 per 1000 (50 to 166)
Adverse events, including surgical complications and conversion to laparotomy	6 studies reported that there were no conversions to laparotomy. No other studies reported conversion to laparotomy or other complications or adverse effects.
Requirement for further endometrioma surgery Follow‐up: 12 months after surgery	Study population		OR 0.16 (0.07 to 0.41)	178 (2 RCTs)	⊕⊕⊝⊝ Lowa,b
	318 per 1000	69 per 1000 (32 to 161)
Spontaneous pregnancy rate Follow‐up: 12 months after surgery	Study population		OR 1.27 (0.33 to 4.87)	101 (3 RCTs)	⊕⊕⊝⊝ Lowa,c
	170 per 1000	206 per 1000 (63 to 499)
Pregnancy rate following fertility treatment Follow‐up: 12 months after surgery	Study population
	No study reported this outcome.
*The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; OR: odds ratio.
GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

^a Downgraded one level for serious imprecision (few participants).
^b Downgraded one level for serious risk of bias (lack of blinding and unclear randomisation processes).
^c Downgraded one level for serious inconsistency (unexplained statistical heterogeneity).

Background

Description of the condition

Endometriosis is a common pelvic inflammatory condition associated with pelvic pain and infertility in women (Hart 2016). It is characterised by lesions of endometrial‐like tissue outside the uterus (Johnson 2017). Some women with the condition have no symptoms. Endometriotic deposits have been found in up to 22% of asymptomatic women and up to 45% of women with pelvic pain (Ajossa 1994; Farquhar 2000). Three common manifestations of the disease are peritoneal endometriosis, endometriomas (deposits in or on the ovaries), and deep infiltrating endometriosis (Hirsch 2017). The mechanisms leading to endometriosis are not fully understood. One popular hypothesis suggests that the condition is caused by shedding of menstrual endometrium and its dissemination throughout the pelvis (Cullen 1920; Sampson 1927; Hart 2016)

Studies have estimated that up to 44% of women with endometriosis have endometriomas, which are often associated with a severe form of the disease (Jenkins 1986; Redwine 1999). The origin of ovarian endometriomas is unknown, but the leading theory is that they arise from a deposit of endometrium passed through the fallopian tube (the transplantation theory; Sampson 1927), causing adherence of the ovary to the pelvic peritoneum and progressive invagination (folding inwards) of the ovary (Brosens 1994; Brosens 1996; Hughesdon 1957; Nisolle 1997). If this is true, endometriomas are pseudocysts (false cysts) formed by inversion of the ovarian cortex (centre), and removal of this cyst wall might involve removal of normal ovarian tissue with possible adverse implications for future fertility (Vercellini 2003). Not all endometriomas cause pain, and when they are small, the associated risk of ovarian torsion or malignant transformation is low. Consequently, deciding on a management strategy (surgical or conservative) poses a clinical dilemma, especially during fertility treatment.

The potential mechanisms of endometrioma‐associated infertility include reduced oocyte and embryo quality due to chronic inflammation, and altered follicular environment and reduced ovarian reserve due to increased tissue oxidative stress and localised inflammatory reaction (de Ziegler 2010; Jayaprakasan 2017). Endometriomas can cause pain through mass effect, adherence to other pelvic organs such as the bowel, localised inflammation, and altered local milieu of prostaglandins and prostacyclins that regulate pain pathways. Removal of an endometrioma may also involve removal of normal ovarian tissue, potentially reducing the number of primordial follicles in the ovary (ovarian reserve). It is important to evaluate the potential negative impact of surgery on ovarian reserve against any potential benefit (Jayaprakasan 2017).

Available measures of ovarian reserve are antral follicle count (AFC) and serum anti‐Müllerian hormone (AMH) levels. AMH is produced by the granulosa cells of the pre‐antral and small antral follicles in the ovary. There is growing evidence of its clinical utility as an accurate measure of ovarian reserve for predicting poor and excessive ovarian responses as part of in‐vitro fertilisation (IVF) treatment. It may also be useful for diagnosing ovarian failure and polycystic ovary syndrome (PCOS). Clinicians can assess AFC during transvaginal ultrasound by counting follicles that measure between 2 mm and 10 mm in each ovary. AMH testing is simpler than AFC, but multiple studies have shown the two measures to be equally accurate (LaMarca 2014). For women of reproductive age who may require fertility treatment in the future, the preferred surgical technique for managing endometrioma is that which causes the smallest decline in AMH and AFC (Dewailly 2013; Li 2016). Ovarian volume is another potential indicator of ovarian reserve, but it is rarely used for clinical prediction given the inter‐ and intra‐cycle variability and lack of sensitivity (Jayaprakasan 2008).

Description of the intervention

The primary indications for treatment of ovarian endometrioma are pelvic pain and dyspareunia (pain during or after sexual intercourse; Vercellini 1997). Endometrioma may impair the outcomes of fertility treatment, although this hypothesis is controversial (Yanushpolsky 1998). There is a small increased risk of ovarian cancer in women with endometriosis (Nishida 2000), with an increase in lifetime incidence from 1% to 2% in the presence of an endometrioma, but this should not influence clinical decision‐making about management. Treatment of incidental disease in otherwise asymptomatic women is currently not recommended, as the development and natural course of endometriomas is not well understood (Jayaprakasan 2017).

Endometriomas reduce in size by up to 57% with anti‐oestrogen medical treatment, but this is also contraceptive, so unsuitable for women who wish to become pregnant (Farquhar 1998). In addition, endometriomas may rupture or tort and reduce access to ovarian follicles at egg collection for IVF, though the evidence for these outcomes is controversial.

When surgical treatment of ovarian endometriomas is necessary, laparoscopy is the gold standard (Daniell 1991; Donnez 1996; Sutton 1997; Yuen 1997). Compared to laparotomy, laparoscopy is associated with shorter hospital stay, faster recovery, decreased costs, and lower incidence of new pelvic adhesions (Luciano 1989; Luciano 1992; Lundorff 1991; OLSG 1991); consequently, laparoscopy is widely accepted as the preferred approach (Adamson 1992; Bateman 1994; Busacca 1998; Canis 2003; Catalano 1996; Crosignani 1996; Milingos 1999; Sawada 1999). The risk of conversion to laparotomy is extremely low and generally results from intraoperative complications such as blood vessel or viscus injury. Associated factors include the experience of the surgeon, the complexity of the surgery, and patient characteristics such as body mass index (Sokol 2003).

The laparoscopic techniques available for the treatment of ovarian endometrioma are cyst wall laser vaporisation (destruction by burning) with or without prior medical therapy (Brosens 1996; Donnez 1996; Mircea 2016; Sutton 1997), drainage and ablation (diathermy or laser), and cystectomy. (Canis 1992; Martin 1991; Reich 1986). In this review, we will compare drainage and cystectomy (excision) with drainage and ablation.

Cystectomy or excision of the cyst involves the opening of the endometrioma with or without the use of electrosurgical or laser energy. The wall of the endometrioma is then excised or 'stripped away' from the underlying cortex using a combination of scissors (or a monopolar hook) and grasping forceps. Ablation of the endometrioma also involves the opening and drainage of the endometrioma, or fenestration (making a window in the wall of the cyst), followed by the destruction of the cyst wall using either electrosurgical current (cutting or coagulating diathermy) or a form of carbon dioxide (CO₂) laser energy (Jones 2000). Where possible, the cyst should be everted to expose the inner cyst wall completely. Once the cyst is everted, the cystic lining is completely vaporised using CO₂ fibre laser in a radial way starting from the centre and moving to the periphery at a power density of approximately 13W/cm² (Giampaolino 2015; Pados 2009).

Based on current evidence, drainage and ablation of endometrioma is not recommended due to the high rate of cyst recurrence (Donnez 1994; Hart 2016; Vercellini 1992). However, it is uncertain whether excision of the cyst capsule with the stripping technique (cystectomy) is preferable to drainage and ablation for pain and fertility. One previous meta‐analysis of randomised controlled trials (RCTs) found favourable evidence for cystectomy compared with drainage and ablative (diathermy or laser) techniques in terms of spontaneous pregnancy and recurrence rates (Hart 2008). However, cystectomy may remove more normal ovarian tissue and reduce ovarian reserve (Candiani 2018; Dunselman 2014).

Pados and colleagues described a variation of the standard drainage and ablation surgery (Pados 2009). They compared excision with a novel three‐step procedure, which involved: an initial laparoscopy with drainage of the cyst contents, irrigation, and inspection of its inner wall; routine histological examination of a cyst wall biopsy to confirm the diagnosis of endometriosis; three months of treatment with gonadotropin‐releasing hormone (GnRH) agonists to reduce cyst diameter, stromal vascularisation, and mitotic activity of endometriosis; and a second laparoscopy to vaporise the inner cyst wall with a CO₂ laser (Pados 2009).

How the intervention might work

The aetiology of endometrioma‐associated pain is multifactorial, involving mass effect, adhesions, distortion of surrounding tissue, and an altered physiological environment with impact on prostaglandins, inflammatory, and nerve pathways. Surgical removal of endometrioma may relieve the mass effect of the cyst and reduce associated pelvic inflammation. In addition, as part of the same operation, the surgeon can remove other peritoneal endometriotic tissue visualised during laparoscopy to normalise the pelvic anatomy (Jones 2002).

Why it is important to do this review

In the surgical management of endometriomas, it is important to choose the technique that will offer maximum benefit to women in terms of pain reduction, prevention of cyst recurrence, and fertility outcomes. Surgical techniques and equipment have evolved considerably since the first version of this review was published (Hart 2005), which is why we wish to revisit the clinical question of cystectomy versus drainage and ablation. Endometrioma and associated endometriosis is a chronic condition that often requires repeat surgery due to high recurrence rates. Therefore, it is crucial to identify which treatment modality will reduce the need for women to return to theatre for treatment (Dunselman 2014).

Objectives

To evaluate the safety and efficacy of laparoscopic excision (cystectomy) compared with laparoscopic drainage and ablation of endometrioma in women of reproductive age.

Methods

Criteria for considering studies for this review

Types of studies

We included RCTs comparing cystectomy (excision) with drainage and ablation of ovarian endometrioma. Quasi‐RCTs and cross‐over studies were ineligible.

Types of participants

Eligible participants were women with ovarian endometrioma undergoing surgery for the indication of pain, infertility, or both. Endometrioma were defined as endometriotic cysts within or attached to the ovary measuring at least 3 cm in diameter on transvaginal ultrasonography.

Women with gynaecological cancer or with ovarian cysts other than endometriomas were ineligible.

Types of interventions

We compared laparoscopic excision (cystectomy) versus laparoscopic drainage and ablation of the endometrioma capsule. Ablation could be carried out either electrosurgically with bipolar energy (diathermy) or by CO₂ laser.

Types of outcome measures

Primary outcomes

• Recurrence of pelvic pain, including dysmenorrhoea (painful menstrual periods) and dyspareunia, up to two years after surgery

• Adverse events, including surgical complications and conversion to laparotomy

Secondary outcomes

• Recurrence of endometrioma during the 12 months after surgery

• Requirement for further endometrioma surgery during the 12 months after surgery

• Subsequent fertility

  • Spontaneous pregnancy rate in women trying to conceive during the 12 months after surgery

  • Pregnancy rate following fertility treatment (controlled ovarian hyperstimulation and intrauterine insemination) during the 12 months after surgery

  • Live birth rate

• Ovarian reserve

  • Serum AMH at three months and six to 12 months after surgery

  • AFC at six to 12 months after surgery

  • Ovarian volume, as assessed by vaginal ultrasound, at six to 12 months after surgery

• Ovarian response to controlled ovarian hyperstimulation (number of dominant follicles obtained)

Search methods for identification of studies

We searched for all reports, published and unpublished, that described RCTs of excision versus ablation for surgical management of endometrioma in women with pain, infertility, or both. We applied no restrictions related to the language, date, or type of publication. In consultation with the Cochrane Gynaecology and Fertility Group Information Specialist, we compiled detailed search strategies to identify relevant studies.

Electronic searches

We searched the following electronic databases for relevant trials.

• The Cochrane Gynaecology and Fertility Group's specialised register of controlled trials, ProCite platform, (searched 19 December 2022; Appendix 1). This register contains published and unpublished trials and conference abstracts.

• Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CSRO), Web platform (searched 19 December 2022; Appendix 2)

• MEDLINE Ovid (1946 to 19 December 2022; Appendix 3)

• Embase Ovid (1980 to 19 December 2022; Appendix 4)

• PsycINFO Ovid (1806 to 19 December 2022; Appendix 5)

• CINAHL EBSCO (1982 to March 2020; Appendix 6). All references after the 2020 search were included in the 2022 CENTRAL search output.

We combined the MEDLINE search with the Cochrane highly sensitive search strategy for identifying randomised trials (Lefebvre 2024). The Embase and CINAHL searches were combined with trial filters developed by the Scottish Intercolegiate Guidelines Network (SIGN; www.sign.ac.uk/what-we-do/methodology/search-filters/).

Searching other resources

We also searched the following sources to December 2022.

• US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (www.clinicaltrials.gov) and World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch), in all fields using the words 'ovarian cyst', 'laparotomy', 'laparoscopy', 'ovarian surgery', 'endometrioma'

• Web of Knowledge for conference proceedings and published trials

• Google using the keywords 'endometrioma/endometriomata' and 'excision' or 'ablation'

• PubMed for recent trials not yet indexed in the major databases

• Handsearch of relevant journals and conference abstracts not covered in the Cochrane Gynaecology and Fertility Group's specialised register

In addition, we checked the reference lists of relevant trials and systematic reviews retrieved by the search, and contacted experts in the field to obtain any additional trials.

Data collection and analysis

We conducted data collection and analysis in accordance with the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2023).

Selection of studies

Two review authors (RK, RM) independently screened the titles and abstracts of all records retrieved by the search, excluding those that were clearly irrelevant. Next, we retrieved the full‐text articles of all potentially eligible studies, and the same two review authors independently examined the articles against our eligibility criteria. We contacted study authors as required to clarify study eligibility. We resolved disagreements by discussion or by consulting a third review author (MH or RH) if necessary.

Data extraction and management

Two review authors (RK, RM) independently extracted data from the included studies using data extraction forms, resolving any disagreements by discussion. We sought further information from study authors as needed (e.g. for studies published as abstract only). We collected study characteristics and outcome data, which we presented in the Characteristics of included studies table as stipulated in the Cochrane Handbook for Systematic Review of Interventions (Higgins 2023).

Assessment of risk of bias in included studies

Two review authors (RK, RM) independently assessed the included studies for risk of bias using the Cochrane risk of bias tool RoB 1, which covers the following domains (Higgins 2017).

• Selection bias (sequence generation and allocation concealment)

• Performance bias (blinding of participants and personnel)

• Detection bias (blinding of outcome assessors)

• Attrition bias (completeness of outcome data)

• Reporting bias (selective outcome reporting)

• Other potential sources of bias.

RK and RM assigned one of three judgements (high risk of bias, low risk of bias, or unclear) to each study for each domain. They resolved any disagreements by discussion with senior review authors. All judgements are described fully in the Characteristics of included studies table. We incorporated the judgements into the interpretation of review findings by means of a sensitivity analysis. The risk of bias judgements also fed into the GRADE assessment of the certainty of the evidence. We took care to search for within‐study selective reporting (e.g. trials that did not report outcomes such as live birth or reported them in insufficient detail). Where protocols were available, we assessed studies for differences between study protocols and published results.

Measures of treatment effect

For dichotomous outcomes such as pregnancy rate and pelvic pain, we used the number of events in the control and intervention groups of each study to calculate the Mantel‐Haenszel odds ratios (ORs). For continuous outcomes such as AMH levels, we calculated the mean difference (MD) between treatment groups. We presented 95% confidence intervals (CIs) for all effect estimates.

Unit of analysis issues

To avoid counting multiple treatment attempts, we scrutinised the studies to check that women were only included at the time of the initial procedure.

The primary analysis was per woman except in one trial where each ovary received a different treatment (Var 2011). We deemed it inappropriate to include this trial in the meta‐analyses, so we presented the data separately.

Dealing with missing data

Wherever possible, we analysed data on an intention‐to‐treat basis. We attempted to obtain missing data from the original trial authors as needed. If these data were unavailable, we analysed only the available data.

Assessment of heterogeneity

We pooled outcomes when no clinical heterogeneity was apparent. To examine statistical heterogeneity between the results of different studies, we inspected the scatter in the data points on the forest plots and the overlap in their CIs. We also used the Chi² test and the I² statistic. A poor overlap of the CIs and a low P value or large Chi² statistic relative to the degree of freedom indicated heterogeneity. To interpret the I² values, we used the following rough thresholds (Higgins 2023).

• 0% to 40%: might not be important

• 30% to 60%: may represent moderate heterogeneity

• 50% to 90%: may represent substantial heterogeneity

• 75% to 100%: considerable heterogeneity

If we detected substantial heterogeneity, we explored possible explanations in subgroup analyses (e.g. differing populations) or sensitivity analyses. We took any statistical heterogeneity into account when interpreting the results, especially if there was any variation in the direction of effect.

Assessment of reporting biases

Had we included more than 10 RCTs in a single meta‐analysis, we would have created a funnel plot to examine publication bias.

Data synthesis

We analysed the data using RevMan (RevMan 2024). We combined data from included studies using a fixed‐effect model.

We organised the forest plots so that increases in the probability of a particular outcome – which may be beneficial (e.g. spontaneous pregnancy) or detrimental (e.g. recurrence of pain, endometrioma) – were to the right of the centre line (null value), and decreases in the probability of a particular outcome were to the left of the centre line.

Subgroup analysis and investigation of heterogeneity

We planned to perform subgroup analysis according to the indication for ovarian endometrioma surgery (pain or infertility). We conducted a post‐hoc subgroup analysis according to type of ablation (standard compared with three‐step procedure).

Sensitivity analysis

We conducted sensitivity analyses for the primary outcomes to determine whether the conclusions were robust to arbitrary decisions made regarding the eligibility and analysis. We tested the following alternative decisions.

• Restricting the analysis to studies without significant risk of bias (defined as studies at low risk of selection bias)

• Using a random‐effects model

• Using relative risk (RR) rather than OR as the summary effect measure

Summary of findings and assessment of the certainty of the evidence

We prepared a summary of findings table using GRADEpro GDT and following Cochrane methods (Schünemann 2023). The table included the following outcomes.

• Recurrence of dysmenorrhoea

• Recurrence of dyspareunia

• Adverse events, including surgical complications and conversion to laparotomy

• Recurrence of endometrioma

• Requirement for further endometrioma surgery

• Spontaneous pregnancy rate

• Pregnancy rate following fertility treatment

Two review authors independently rated the certainty of the evidence for each outcome as high, moderate, low, or very low based on the five GRADE considerations: risk of bias, consistency of effect, imprecision, indirectness, and publication bias. We resolved any disagreements by discussion. Judgements were justified, documented, and incorporated into the reporting of results for each outcome.

Results

Description of studies

Results of the search

The original 2008 review included three RCTs (Hart 2008), but we listed two of them as awaiting classification in this update pending further details about study design and conduct (Alborzi 2004; Alborzi 2007). The search conducted in 2022 returned 2154 records (1598 without duplicates). After removing irrelevant records during the title and abstract screen, we considered 22 full‐text papers. Seven new studies (eight records) met our inclusion criteria (Candiani 2018; Carmona 2011; Giampaolino 2015; Munrós 2019; Pados 2009; Salem 2013; Var 2011). We also included one previously excluded study after confirming it was an RCT (Fulop 2006). Two new studies are awaiting classification (Rius 2020; Shaltout 2019). The remaining studies were ineligible (see Characteristics of excluded studies table). Figure 1 illustrates the study selection process in a PRISMA flow diagram.

1.

PRISMA diagram illustrating the study selection process.

Included studies

This updated review included nine RCTs (Beretta 1998; Candiani 2018; Carmona 2011; Fulop 2006; Giampaolino 2015; Munrós 2019; Pados 2009; Salem 2013; Var 2011).

Participants and setting

In total, 578 women participated in the included studies, which took place in tertiary hospitals or university teaching hospitals. Sample sizes ranged from 20 women (Pados 2009) to 104 women (Fulop 2006). In all RCTs, the indication for surgery was the presence of an endometrioma measuring at least 3 cm, assessed by ultrasound examination in the context of pain, infertility, or both. Exclusion criteria were previous surgery for endometriosis or use of hormone suppression therapy over the preceding six months. The age range was 18 to 40 years. Overall, participants were well balanced across the study arms in terms of baseline demographics and clinical characteristics (pain and history of infertility).

Interventions

All studies evaluated laparoscopic management of ovarian endometrioma by cystectomy (excision) versus drainage and ablation with either bipolar electrocoagulation or CO₂ laser. The cystectomy method was similar in all studies, and involved the inner lining of the cyst being stripped away from normal ovarian tissue with surgical grasping forceps. In the drainage and ablation groups, the surgeon drained the cyst, took a biopsy of the cyst wall, and ablated the cyst wall using bipolar coagulation or laser energy.

Pados 2009 evaluated a modified approach to the drainage and ablation procedure (the three‐step procedure described in Description of the intervention).

Var 2011 included women with bilateral endometrioma, and all participants had both types of surgery (cystectomy on one side and drainage and ablation on the other side). The outcomes were reported per ovary, and the data were unsuitable for meta‐analysis in this review.

Follow‐up

Follow‐up ranged from three to 12 months in six studies (Candiani 2018; Giampaolino 2015; Munrós 2019; Pados 2009; Salem 2013; Var 2011). In Beretta 1998, women were followed for up to 26 months (with a median follow‐up of 20 months in the excisional group and 19.5 months in the drainage and ablation group). The longest follow‐up of the included studies was 60 months (Carmona 2011). Fulop 2006 did not specify the duration of follow up.

Outcomes

Primary outcomes

Recurrence of pelvic pain

We determined the percentage of women with significant pelvic pain after surgery by referring to the publications and contacting some study authors for clarification. Since the surgical procedures themselves cause discomfort, a formal comparison of the two techniques immediately after surgery is problematic (Alborzi 2004; Beretta 1998). Recurrence of pelvic pain was assessed at three‐monthly intervals after the operation, up to 24 months in some studies. One study used a visual analogue scale (VAS) of 1 to 10 points, where 5 to 7 points represented moderate pain and 8 to 10 points represented severe pain (Beretta 1998). Other studies simply reported the number of women with recurrence of pain symptoms. Beretta 1998 reported dysmenorrhoea, deep dyspareunia, and pelvic pain separately.

Adverse events, including surgical complications and conversion to laparotomy

Five studies reported the rate of conversion to laparotomy (Beretta 1998; Carmona 2011; Pados 2009; Salem 2013; Var 2011).

Secondary outcomes

Recurrence of endometrioma

Three studies reported recurrence of ovarian endometriomas measured by ultrasound examination at six months and 12 months after surgery (Beretta 1998; Pados 2009; Var 2011). Carmona 2011 evaluated recurrence with ultrasound at 12 and 60 months of follow‐up. Recurrence was defined as the presence of a cyst measuring at least 3 cm in diameter on transvaginal ultrasound, with features suggestive of endometrioma. Fulop 2006 reported recurrence of endometrioma without specifying the method of measurement.

Requirement for further endometrioma surgery

Two studies reported the requirement for further endometrioma surgery after the initial laparoscopic procedure (Beretta 1998; Fulop 2006).

Subsequent fertility

Four RCTs assessed fertility‐related outcomes in a subset of women who wished to conceive (Beretta 1998; Candiani 2018; Carmona 2011; Var 2011). The outcomes were time to spontaneous conception and the percentage of women conceiving naturally.

Three RCTs followed the women for 12 months after surgery (Candiani 2018; Carmona 2011; Var 2011). Carmona 2011 also extended their follow‐up of pregnancy outcomes to 60 months, but this included pregnancies achieved through assisted reproductive technology.

Carmona 2011 recorded pregnancy rates without specifying the method of pregnancy confirmation. The remaining RCTs recorded clinical pregnancy, defined as the presence of a gestational sac on ultrasound examination (Beretta 1998; Var 2011).

Ovarian reserve and ovarian response

Three RCTs measured serum AMH at three months (Candiani 2018; Giampaolino 2015; Salem 2013), and two studies measured serum AMH at six months (Pados 2009; Salem 2013). Four RCTs measured AFC at six months (Candiani 2018; Pados 2009; Salem 2013; Var 2011).

Var 2011 reported the number of dominant follicles per ovary in IVF treatment. The publication did not specify the dosage and preparation of gonadotropin, but a long GnRH agonist protocol was used in all women.

Three studies reported ovarian volume (Candiani 2018; Pados 2009; Salem 2013). All used the prolate ellipsoid formula for the calculation (length × height × width × 0.523).

Excluded studies

The main reasons for exclusion of studies during the full‐text review were related to study design (non‐randomised) or the intervention (cystectomy versus a combination procedure of cystectomy and drainage and ablation). The Characteristics of excluded studies table provides further details.

Studies awaiting classification

Four studies may be eligible for inclusion and are awaiting classification pending confirmation of some study details (Alborzi 2004; Alborzi 2007; Rius 2020; Shaltout 2019).

Ongoing studies

We identified one ongoing study taking place in Egypt (NCT03615352). It aimed to recruit 92 women and had a planned completion date of December 2018. We found no published data for this trial.

Risk of bias in included studies

Figure 2 and Figure 3 present the risk of bias assessment results in a visual format.

2.

Review authors' judgements about each risk of bias item presented as percentages across all included studies.

3.

Review authors' judgements about each risk of bias item for each included study.

Allocation

Random sequence generation

Five studies used computer‐generated randomisation sequences so were at low risk of bias for this domain (Beretta 1998; Candiani 2018; Carmona 2011; Giampaolino 2015Munrós 2019). Three studies provided insufficient details on the randomisation process, so the risk of bias was unclear (Fulop 2006; Salem 2013; Var 2011). Pados 2009 used opaque envelopes that were distributed by the clinic trial secretaries. We felt this was an inadequate method, and we judged the study at high risk of bias.

Allocation concealment

We judged four studies at low risk of selection bias for allocation concealment because they used adequate methods such as opaque sealed envelopes (Beretta 1998; Carmona 2011; Giampaolino 2015; Pados 2009). The remaining studies provided insufficient information to make a judgement (unclear risk).

Blinding

Blinding of participants and personnel

We considered Munrós 2019 at low risk of performance bias because all women were blinded to the intervention. Two trials provided insufficient information to make a judgement, so were at unclear risk (Fulop 2006; Var 2011). The remaining studies did not blind the women to treatment allocation, and we considered that knowledge of the intervention could influence the women's subjective assessment of pain; therefore, we judged them at high risk of performance bias.

Blinding of outcome assessors

Four studies blinded the ultrasonographers measuring outcomes such as follicle count, so were at low risk of detection bias (Candiani 2018; Giampaolino 2015; Munrós 2019; Var 2011). Two studies did not blind the ultrasonographers, so were at high risk (Beretta 1998; Pados 2009). The remaining studies provided insufficient information about the blinding of outcome assessors to make a judgement (unclear risk).

Incomplete outcome data

Four studies provided insufficient information to make a judgement, so were at unclear risk of attrition bias (Fulop 2006; Giampaolino 2015; Salem 2013; Var 2011). For the other studies, we were able to obtain sufficient data to make a low‐risk judgement, in some cases from study authors (Beretta 1998; Pados 2009).

Selective reporting

We considered five studies at low risk of reporting bias because they reported all prespecified outcomes in full (Beretta 1998; Candiani 2018; Carmona 2011; Munrós 2019; Pados 2009). For the remaining studies, the risk of reporting bias was unclear owing to lack of information (Fulop 2006; Giampaolino 2015; Salem 2013; Var 2011).

Other potential sources of bias

We identified no other potential sources of bias, so we judged all trials at low risk of other bias.

Effects of interventions

See: Table 1

Primary outcomes

Recurrence of pelvic pain

Dysmenorrhoea

Two studies reported recurrence of dysmenorrhoea (Beretta 1998; Fulop 2006). At up to two years after surgery, excision compared with drainage and ablation may reduce the risk of dysmenorrhoea recurrence (OR 0.25, 95% CI 0.12 to 0.52; I² = 0%; 2 studies, 140 women; low‐certainty evidence; Analysis 1.1; Table 1).

1.1. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 1: Recurrence of pelvic pain

Using the random‐effects model instead of the fixed‐effect model did not change the results, and the RR is similar to the OR (RR 0.39, 95% CI 0.23 to 0.66).

Recurrence of dysmenorrhoea may occur in 49% of women after ablative surgery compared with 10% to 34% after excisional surgery.

Dyspareunia

Two studies reported recurrence of dyspareunia (Beretta 1998; Fulop 2006). At up to two years after surgery, excision compared with drainage and ablation may reduce the risk of dyspareunia recurrence (OR 0.09, 95% CI 0.03 to 0.22; I² = 0%; 2 studies, 131 women; low‐certainty evidence; Analysis 1.1; Table 1). Recurrence of dyspareunia may occur in 58% of women after ablative surgery compared with 4% to 23% after excisional surgery.

We found no important differences in the result when we removed one study at unclear risk of selection bias (OR 0.08, 95% CI 0.01 to 0.51), when we used the random‐effects model instead of the fixed‐effect model, or when we calculated the RR instead of the OR (RR 0.20, 95% CI 0.10 to 0.39).

Adverse events, including surgical complications and conversion to laparotomy

Five studies reported that there were no conversions to laparotomy (Beretta 1998; Carmona 2011; Pados 2009; Salem 2013; Var 2011). No studies reported any other surgical complications or adverse effects.

Secondary outcomes

Recurrence of endometrioma

Five studies measured recurrence of endometrioma (Beretta 1998; Carmona 2011; Fulop 2006; Pados 2009; Var 2011), but Var 2011 reported the results per ovary so could not be included in our meta‐analysis. Excision compared with drainage and ablation may reduce the risk of recurrence of endometrioma in the 12 months after surgery (OR 0.17, 95% CI 0.09 to 0.34; I² = 0%; 4 studies, 264 women; low‐certainty evidence; Analysis 1.2; Table 1). Recurrence of endometrioma may occur in 37% of women after ablative surgery compared with 5% to 17% after excisional surgery.

1.2. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 2: Recurrence of endometrioma

When we performed a subgroup analysis according to type of drainage and ablation (standard versus three‐step procedure), the results were consistent with the overall direction of effect.

Var 2011 reported recurrence of endometrioma in 0/37 ovaries treated with cystectomy and in 2/37 ovaries treated with coagulation.

Requirement for further endometrioma surgery

Two studies reported requirement for further endometrioma surgery (Carmona 2011; Fulop 2006). Excision compared with drainage and ablation may reduce the need for further endometrioma surgery in the 12 months after the operation (OR 0.16, 95% CI 0.07 to 0.41; I² = 51%; 2 studies, 178 women; low‐certainty evidence; Analysis 1.3; Table 1).

1.3. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 3: Requirement for further endometrioma surgery

Our results suggest that 32% of women require further endometrioma surgery after ablative surgery compared with 3% to 16% after excisional surgery.

Subsequent fertility

Spontaneous pregnancy rate

Three studies reported spontaneous pregnancy rates (Beretta 1998; Candiani 2018; Carmona 2011). There may be little or no difference in spontaneous pregnancy rates at 12 months in women who undergo excisional surgery compared with those who undergo ablative surgery (OR 1.27, 95% CI 0.33 to 4.87; I² = 35%; 3 studies, 101 women; low‐certainty evidence) (Analysis 1.4; Table 1).

1.4. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 4: Spontaneous pregnancy rate over the 12 months after surgery

Pregnancy rate following fertility treatment

No studies reported data relating to pregnancy rates following fertility treatment.

Ovarian reserve

Serum anti‐Müllerian hormone

Three studies measured serum AMH in the short term (at three months: Candiani 2018; Giampaolino 2015; Salem 2013), and two studies measured serum AMH in the long term (six months: Pados 2009; Salem 2013). All studies measured serum AMH in ng/mL using a commercial enzyme‐linked immunosorbent assay (ELISA) kit. For Pados 2009 and Salem 2013, the ELISA kit was provided by Diagnostic System Laboratories Inc. Candiani 2018 used the AMH Gen II ELISA, Beckman Coulter assay. Pados 2009 did not state the assay used. Our meta‐analysis pooled the values for decrease in serum AMH, meaning values above 0 represented a negative outcome. The results suggested that excision compared with drainage and ablation had little or no effect on decrease in AMH levels at three months (MD 0.07 ng/mL, 95% CI −0.16 to 0.29; I² = 0%; 3 studies, 208 women; Analysis 1.5) and six months (MD −0.39 ng/mL, 95% CI −1.35 to 0.57; I² = 60%; 2 studies, 120 women; Analysis 1.6).

1.5. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 5: Serum anti‐Müllerian hormone levels (ng/mL) three months after surgery (short term)

1.6. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 6: Serum anti‐Müllerian hormone levels (ng/mL) six months after surgery

When we performed a subgroup analysis according to type of drainage and ablation (standard versus three‐step procedure), the results were similar (Analysis 1.6).

Antral follicle count

Four studies measured AFC by vaginal ultrasound six months after surgery (Candiani 2018; Pados 2009; Salem 2013; Var 2011), but Var 2011 reported the results per ovary so could not be included in our meta‐analysis. AFC was lower in the excision group than in the drainage and ablation group (MD −1.44 follicles, 95% CI −2.70 to −0.18; I² = 80%; 3 studies, 180 women; Analysis 1.7).

1.7. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 7: Antral follicle count (number of follicles) six months after surgery

When we performed a subgroup analysis according to type of drainage and ablation (standard versus three‐step procedure), the results were consistent with lower AFC in the excision group (MD −1.98 follicles, 95% CI −2.67 to −1.29).

Var 2011 reported a mean AFC of 3.67 follicles (standard deviation (SD) 1.26) in the ovaries treated with excision and 4.75 follicles (SD 0.6) in the ovaries treated with ablation.

Ovarian volume

Four studies measured ovarian volume in cm³ by vaginal ultrasound six months after surgery (Candiani 2018; Pados 2009; Salem 2013; Var 2011), but Var 2011 reported the results per ovary so could not be included in our meta‐analysis. According to our results, ovarian volume was lower after excisional surgery than after ablative surgery, but the 95% confidence interval was also compatible with no effect (MD −1.09 cm³, 95% CI −2.39 to 0.20; I² = 68%; 3 studies, 180 women; Analysis 1.8).

1.8. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 8: Ovarian volume (cm³) six months after surgery

In the study that evaluated the three‐step drainage and ablation procedure, there was no difference between the groups in ovarian volume at six months (MD 0.40 cm³, 95% CI −1.51 to 2.31; 20 women; Analysis 1.8).

Var 2011 reported a mean ovarian volume of 6.27 cm³ (SD 1.95) in the ovaries treated with cystectomy (n = 37) and 9.87 cm³ (SD 2.01) in the ovaries treated with drainage and ablation (n = 37).

Ovarian response to controlled ovarian hyperstimulation

Var 2011 found that during IVF cycles, the response to ovarian stimulation measured by dominant follicle number was higher in the ablation group compared to the excision group (MD −0.67 dominant follicles, 95% CI −1.09 to −0.25; I² = 0%; 74 women; Analysis 1.9).

1.9. Analysis.

Comparison 1: Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy, Outcome 9: Ovarian response (number of dominant follicles) after surgery

Discussion

Summary of main results

This review aimed to establish the best surgical technique for managing ovarian endometriomas. Laparoscopy is the surgical approach of choice because it causes less pain and leads to earlier discharge and a shorter postoperative recovery compared with laparotomy (Mais 1996). Consequently, we focused on two laparoscopic techniques: excision versus drainage and ablation of the ovarian pseudocyst.

Excisional surgery compared with ablative surgery may reduce the risk of dysmenorrhoea and dyspareunia recurrence, endometrioma recurrence, and need for further surgery. The studies that reported need for further surgery followed the women for 12 months. The risk may increase with time due to the progressive nature of endometriosis.

The available evidence suggests little or no difference between the surgical techniques in the probability of subsequent spontaneous pregnancy.

Five studies reported that there were no intraoperative conversions to laparotomy. This is reassuring, as it shows that ovarian endometriomas can be surgically managed through a minimally invasive approach in most cases, leading to faster recovery times. No studies described other intraoperative complications or adverse events.

The effect of surgical excision compared with ablation on ovarian reserve (measured by serum AMH levels and AFC) and ovarian volume is uncertain. There may be a lower AFC and lower ovarian response in women who have undergone ovarian cystectomy than those women who have undergone ablation of their endometrioma; however, further RCTs are needed to confirm this. Endometriosis and endometriomas tend to be associated with infertility, and it is important to understand the impact of each surgical modality on ovarian reserve, particularly in women who may have assisted reproductive treatment in the future.

Overall completeness and applicability of evidence

The included studies are reasonably representative of the population of interest, which means our findings are largely applicable to women who undergo surgery for endometrioma. However, we were unable to fully answer all our research questions. While we identified a fairly large body of evidence relating to pelvic pain, recurrence of endometrioma, and the need for further surgery, there was insufficient information on adverse effects, surgical complications, and the probability of pregnancy after surgery.

Quality of the evidence

The risk of bias in the included studies was generally low, except for performance bias in relation to the primary outcome of pelvic pain, as women's knowledge of their treatment allocation could influence their subjective perception of pain. Furthermore, it was unclear in many studies whether outcome assessors were blinded, so the risk of detection bias was unclear. In addition to risk of bias, we downgraded the certainty of evidence for imprecision due to the low numbers of participants in the included studies, and for inconsistency due to statistical heterogeneity.

Potential biases in the review process

We made every attempt to reduce bias in the review process by carrying out a comprehensive literature search and by having two reviewers independently screen the search results, extract data, assess the risk of bias, and rate the certainty of the evidence. One potential limitation of the review is that we may have overlooked some studies in the non‐English literature, although we did not restrict the search to English‐only publications.

Agreements and disagreements with other studies or reviews

Our findings are in line with current evidence regarding the effect of endometrioma surgery on fertility (Jayaprakasan 2017). There are still many uncertainties about the optimal treatment of endometriomas, and large RCTs incorporating modern treatment modalities are required. Therefore, based on the available evidence, we conclude that management decisions should be individualised according to the patients’ age, ovarian reserve, and the primary indication for surgery (pain or infertility).

Authors' conclusions

Implications for practice.

In the treatment of ovarian endometriomas, excisional surgery compared with ablative surgery may reduce the risk of dysmenorrhoea and dyspareunia recurrence, the risk of endometrioma recurrence, and the need for further endometrioma surgery. There may be little or no difference between the techniques in terms of their effect on spontaneous pregnancy. There is insufficient evidence on surgical complications and other adverse events.

We found inconsistent evidence on the effect of excisional surgery versus ablative surgery for maintaining ovarian reserve (as measured by serum anti‐Müllerian hormone levels and antral follicle count), and the 95% confidence interval of our effect estimate for ovarian volume after surgery crossed the line of no effect. Further randomised controlled trials are needed to draw more solid conclusions for these outcomes.

Implications for research.

As our conclusions are largely based on low‐certainty evidence, future studies should recruit adequate numbers of women to enable robust and precise estimates of the effect of excisional surgery compared with ablative surgery on pelvic pain and pregnancy outcomes. In particular, future studies should address the impact of surgical technique on reproductive outcomes, with or without infertility treatment.

What's new

Date	Event	Description
26 November 2024	New search has been performed	Inclusion of new secondary outcomes of ovarian function: circulating anti‐Müllerian hormone (AMH), antral follicle count (AFC), and ovarian volume. Seven new studies included (Candiani 2018; Carmona 2011; Giampaolino 2015; Munrós 2019; Pados 2009; Salem 2013; Var 2011). One previously excluded study now included (Fulop 2006). Two previously included studies moved to Awaiting classification pending confirmation of study data (Alborzi 2004; Alborzi 2007).
26 November 2024	New citation required but conclusions have not changed	The addition of new studies has not led to changes in the conclusions of this review.

History

Protocol first published: Issue 4, 2004
Review first published: Issue 3, 2005

Date	Event	Description
8 March 2010	New search has been performed	Updated literature search 31st August 2009 No new RCTs were identified Laparotomy for the management of endometriomata now excluded from review Risk of bias table included
5 May 2008	Amended	Converted to new review format.
18 December 2007	New citation required and conclusions have changed	Substantive amendment
2 September 2007	New search has been performed	Review updated 2 September 2007

Appendices

Appendix 1. Cochrane Gynaecology and Fertility (CGF) specialised register search strategy

Searched 19 December 2022

ProCite platform

Keywords CONTAINS "ovarian adhesions" or "ovarian cyst" or "Ovarian Cysts" or "ovarian endometrioma" or "adnexal cysts" or "adnexal mass" or "endometrioma" or "endometrioma size" or "endometriotic cysts" or "*Endometriosis" or Title CONTAINS"ovarian adhesions" or "ovarian cyst" or "Ovarian Cysts" or "ovarian endometrioma" or "adnexal cysts" or "adnexal mass" or "endometrioma" or "endometrioma size" or "endometriotic cysts" or "*Endometriosis"

AND

Keywords CONTAINS "*Surgical‐Procedures,‐Laparoscopic" or "stripping" or "excision" or "adnexectomy" or "ovarian cystectomy" or "laparoscopic adnexal surgery" or "laparoscopic coagulation techniques" or "laparoscopic ovarian cystectomy" or "laparoscopic stripping" or "laparotomy" or "cystectomy" or "laparoscopic complete excision" or "laparoscopic excision" or "laparoscopic surgery" or "laparoscopic surgical treatment" or "Laparoscopy" or "Laparotomy" or "resection" or "resectoscopic surgery"or"surgery‐gynaecological"or"surgery"or"surgical"or"*Surgical‐Procedures,‐Laparoscopic"or"surgical treatment" or Title CONTAINS "*Surgical‐Procedures,‐Laparoscopic" or "excision" or "adnexectomy" or "ovarian cystectomy" or "endometrioma wall stripping" or "laparoscopic adnexal surgery" or "laparoscopic coagulation techniques" or "laparoscopic electrocautery" or "laparoscopic ovarian cystectomy" or "laparoscopic stripping" or "laparotomy" or "cystectomy" or "laparoscopic complete excision" (575 records)

Appendix 2. CENTRAL CRSO search strategy

Searched 19 December 2022

WEB platform

#1 MESH DESCRIPTOR Endometriosis EXPLODE ALL TREES 923
#2 MESH DESCRIPTOR Ovarian Cysts EXPLODE ALL TREES 1826
#3 MESH DESCRIPTOR adnexal diseases EXPLODE ALL TREES 5205
#4 endometrio*:TI,AB,KY 3128
#5 (ovar* adj5 cyst*):TI,AB,KY 713
#6 #1 OR #2 OR #3 OR #4 OR #5 8446
#7 MESH DESCRIPTOR Laparoscopy EXPLODE ALL TREES 6323
#8 MESH DESCRIPTOR Laparotomy EXPLODE ALL TREES 757
#9 MESH DESCRIPTOR Cystectomy EXPLODE ALL TREES 291
#10 MESH DESCRIPTOR Gynecologic Surgical Procedures EXPLODE ALL TREES 4588
#11 laparoscop*:TI,AB,KY 22504
#12 laparotom*:TI,AB,KY 3627
#13 cystectom*:TI,AB,KY 1695
#14 (excis* adj5 endometrio* ):TI,AB,KY 107
#15 (resect* adj5 endometrio*):TI,AB,KY 46
#16 (surg* adj5 endometrio*):TI,AB,KY 497
#17 #7 OR #8 OR #9 OR #10 OR #11 OR #12 OR #13 OR #14 OR #15 OR #16 29901
#18 #6 AND #17 1823

Appendix 3. MEDLINE search strategy

Searched from 1946 to19 December 2022

OVID platform

1 adnexal diseases/ or ovarian diseases/ or ovarian cysts/ or endometriosis/ (37791)
2 endometrio$.ti,ab,sh. (39185)
3 (ovar$ adj5 cyst$).tw. (12596)
4 or/1‐3 (58776)
5 Laparoscopy/ (100414)
6 laparoscop$.tw. (146112)
7 laparotom$.tw. (53606)
8 cystectom$.tw. (17065)
9 exp Gynecologic Surgical Procedures/ (90538)
10 (excis$ adj5 endometrio$).tw. (867)
11 exp Laparotomy/ (20093)
12 exp Cystectomy/ (10608)
13 (resect$ adj5 endometrio$).tw. (742)
14 (surg$ adj5 endometrio$).tw. (4037)
15 or/5‐14 (305642)
16 4 and 15 (16309)
17 randomized controlled trial.pt. (582930)
18 controlled clinical trial.pt. (95137)
19 randomized.ab. (585732)
20 randomised.ab. (115874)
21 placebo.tw. (240336)
22 clinical trials as topic.sh. (200654)
23 randomly.ab. (397608)
24 trial.ti. (275642)
25 (crossover or cross‐over or cross over).tw. (96054)
26 or/17‐25 (1569425)
27 exp animals/ not humans.sh. (5074784)
28 26 not 27 (1444815)
29 16 and 28 (1035)

Appendix 4. Embase search strategy

Searched from 1980 to 19 December 2022

OVID platform

1 ovary cyst/ or endometriosis/ (53230)
2 adnexa disease/ or ovary disease/ (9830)
3 endometriom$.tw. (4623)
4 (ovar$ adj5 cyst$).tw. (16030)
5 or/1‐4 (69580)
6 Laparoscopy/ (88236)
7 laparoscop$.tw. (234595)
8 laparotom$.tw. (72251)
9 cystectom$.tw. (27421)
10 exp cystectomy/ (33507)
11 exp gynecologic surgery/ (169526)
12 exp laparotomy/ (90801)
13 (excis$ adj5 endometriom$).tw. (447)
14 (resect$ adj5 endometriom$).tw. (109)
15 (surg$ adj5 endometriom$).tw. (839)
16 or/6‐15 (504842)
17 5 and 16 (27062)
18 Clinical Trial/ (1039669)
19 Randomized Controlled Trial/ (736575)
20 exp randomization/ (95813)
21 Single Blind Procedure/ (48500)
22 Double Blind Procedure/ (198511)
23 Crossover Procedure/ (72218)
24 Placebo/ (375048)
25 Randomi?ed controlled trial$.tw. (302029)
26 Rct.tw. (49762)
27 random allocation.tw. (2405)
28 randomly.tw. (522463)
29 randomly allocated.tw. (42909)
30 allocated randomly.tw. (2831)
31 (allocated adj2 random).tw. (854)
32 Single blind$.tw. (29718)
33 Double blind$.tw. (229040)
34 ((treble or triple) adj blind$).tw. (1689)
35 placebo$.tw. (346574)
36 prospective study/ (814176)
37 or/18‐36 (2895141)
38 case study/ (90165)
39 case report.tw. (497427)
40 abstract report/ or letter/ (1214388)
41 or/38‐40 (1788047)
42 37 not 41 (2832215)
43 (exp animal/ or animal.hw. or nonhuman/) not (exp human/ or human cell/ or (human or humans).ti.) (6540452)
44 42 not 43 (2642088)
45 17 and 44 (3066)

Appendix 5. PsycINFO search strategy

Searched from 1806 to 19 December 2022

OVID platform

1 exp Ovaries/ (1011)
2 endometrio$.tw. (383)
3 (ovar$ adj5 cyst$).tw. (54)
4 exp Gynecological Disorders/ (2037)
5 1 or 2 or 3 or 4 (3274)
6 exp Surgery/ (79589)
7 (excis$ adj5 endometrio$).tw. (2)
8 (resect$ adj5 endometrio$).tw. (3)
9 (surg$ adj5 endometrio$).tw. (36)
10 6 or 7 or 8 or 9 (79614)
11 5 and 10 (202)

Appendix 6. CINAHL search strategy

Searched from 1961 to 4 March 2019. All later CINAHL references (post 2019) are included in the CENTRAL CRSO output

EBSCO platform

#	Query	Results
S30	S17 AND S29	349
S29	S18 OR S19 OR S20 OR S21 OR S22 OR S23 OR S24 OR S25 OR S26 OR S27 OR S28	1,305,802
S28	TX allocat* random*	9,892
S27	(MH "Quantitative Studies")	21,880
S26	(MH "Placebos")	11,146
S25	TX placebo*	55,496
S24	TX random* allocat*	9,892
S23	(MH "Random Assignment")	53,574
S22	TX randomi* control* trial*	164,034
S21	TX ( (singl* n1 blind*) or (singl* n1 mask*) ) or TX ( (doubl* n1 blind*) or (doubl* n1 mask*) ) or TX ( (tripl* n1 blind*) or (tripl* n1 mask*) ) or TX ( (trebl* n1 blind*) or (trebl* n1 mask*) )	1,004,218
S20	TX clinic* n1 trial*	239,080
S19	PT Clinical trial	86,754
S18	(MH "Clinical Trials+")	254,529
S17	S6 AND S16	2,642
S16	S7 OR S8 OR S9 OR S10 OR S11 OR S12 OR S13 OR S14 OR S15	37,686
S15	TX resect* N5 endometrio*	187
S14	TX surg* N5 endometrio*	1,502
S13	TX excis* N5 endometrio*	230
S12	TX cystectom*	2,169
S11	TX laparotom*	6,688
S10	TX laparoscop*	30,309
S9	(MM "Cystectomy")	812
S8	(MM "Laparotomy")	1,093
S7	(MM "Laparoscopy") OR (MM "Surgery, Laparoscopic")	13,636
S6	S1 OR S2 OR S3 OR S4 OR S5	9,739
S5	TX ovar* N5 cyst*	1,482
S4	TX endometrio*	6,031
S3	(MM "Adnexal Diseases")	187
S2	(MM "Ovarian Cysts+")	2,946
S1	(MM "Endometriosis")	3,061

Data and analyses

Comparison 1. Excisional surgery versus ablative surgery in the management of ovarian endometrioma by laparoscopy.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Recurrence of pelvic pain	2		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.1.1 Recurrence of dysmenorrhoea	2	140	Odds Ratio (M‐H, Fixed, 95% CI)	0.25 [0.12, 0.52]
1.1.2 Recurrence of dyspareunia	2	131	Odds Ratio (M‐H, Fixed, 95% CI)	0.09 [0.03, 0.22]
1.2 Recurrence of endometrioma	4	264	Odds Ratio (M‐H, Fixed, 95% CI)	0.17 [0.09, 0.34]
1.2.1 Excision vs drainage and ablation	3	244	Odds Ratio (M‐H, Fixed, 95% CI)	0.18 [0.09, 0.35]
1.2.2 Excision vs three‐step drainage and ablation	1	20	Odds Ratio (M‐H, Fixed, 95% CI)	0.16 [0.01, 3.85]
1.3 Requirement for further endometrioma surgery	2	178	Odds Ratio (M‐H, Fixed, 95% CI)	0.16 [0.07, 0.41]
1.4 Spontaneous pregnancy rate over the 12 months after surgery	3	101	Odds Ratio (M‐H, Random, 95% CI)	1.27 [0.33, 4.87]
1.5 Serum anti‐Müllerian hormone levels (ng/mL) three months after surgery (short term)	3	208	Mean Difference (IV, Fixed, 95% CI)	0.07 [‐0.16, 0.29]
1.6 Serum anti‐Müllerian hormone levels (ng/mL) six months after surgery	2	120	Mean Difference (IV, Random, 95% CI)	‐0.39 [‐1.35, 0.57]
1.6.1 Excision vs drainage and ablation	1	100	Mean Difference (IV, Random, 95% CI)	‐0.05 [‐0.38, 0.28]
1.6.2 Excision vs 3 step drainage and ablation	1	20	Mean Difference (IV, Random, 95% CI)	‐1.09 [‐2.33, 0.15]
1.7 Antral follicle count (number of follicles) six months after surgery	3	180	Mean Difference (IV, Random, 95% CI)	‐1.44 [‐2.70, ‐0.18]
1.7.1 Excision vs drainage and ablation	2	160	Mean Difference (IV, Random, 95% CI)	‐1.13 [‐2.93, 0.67]
1.7.2 Excision vs 3 step drainage and ablation	1	20	Mean Difference (IV, Random, 95% CI)	‐1.98 [‐2.67, ‐1.29]
1.8 Ovarian volume (cm3) six months after surgery	3	180	Mean Difference (IV, Random, 95% CI)	‐1.09 [‐2.39, 0.20]
1.8.1 Excision vs drainage and ablation	2	160	Mean Difference (IV, Random, 95% CI)	‐1.55 [‐2.99, ‐0.12]
1.8.2 Excision vs 3 step drainage and ablation	1	20	Mean Difference (IV, Random, 95% CI)	0.40 [‐1.51, 2.31]
1.9 Ovarian response (number of dominant follicles) after surgery	1	74	Mean Difference (IV, Fixed, 95% CI)	‐0.67 [‐1.09, ‐0.25]

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Beretta 1998.

Study characteristics
Methods	Design: RCT Randomisation method: computer randomisation Power calculation: not stated
Participants	Setting: tertiary care hospital Number randomised: 64 Inclusion criteria Age 20–40 years Endometrioma ≥ 3 cm in diameter Exclusion criteria Previous surgery for endometriosis Use of hormone suppressing therapy in the last 6 months
Interventions	Excision of the endometrioma (32 women) versus drainage and bipolar ablation of the endometrioma (32 women)
Outcomes	Recurrence of the symptoms of dysmenorrhoea Deep dyspareunia Non‐menstrual pelvic pain Spontaneous conception
Notes	There were no intraoperative conversions from a laparoscopic approach to a laparotomy. There were no drop‐outs from the study. Pregnancy rate not specifically defined as clinical pregnancy rate. Additional information provided by third author.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer randomisation.
Allocation concealment (selection bias)	Low risk	Participants and surgeons were unaware of allocation prior to surgery.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and surgeons were aware of allocation and this would have contributed to bias in reporting of subjective outcomes such as pain scores.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Patients were aware of surgery.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Low risk	All prespecified outcomes were reported.
Other bias	Low risk	No other indication of any other source of bias.

Candiani 2018.

Study characteristics
Methods	Design: Multicentre randomised study Randomisation method: computer randomisation Power calculation: not stated
Participants	Setting: 2 study centres in Milan, Italy, and Cracow, Poland Number randomised: 30 women to each arm Inclusion criteria Reproductive age Pain, infertility, or both Primary unilateral or bilateral endometriomas Largest diameter of endometrioma 3 cm–8 cm Exclusion criteria: not stated
Interventions	Standardised laparoscopic stripping technique versus drainage of the cyst content, irrigation, and inspection of its inner wall
Outcomes	Change in AFC of operated ovary Changes in serum AMH levels
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation. Assignments were then placed into sealed, numbered, opaque envelopes, which were opened once women consented to participating in the study.
Allocation concealment (selection bias)	Unclear risk	Participants were aware which procedure they were having prior to surgery. Unclear if surgeons were aware of allocation prior to surgery.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and surgeons were aware of allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Serum AMH measures are objective and therefore not subject to bias. Ultrasounds were performed by an experienced sonographer who remained blinded to the type of surgical procedure.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Low risk	All prespecified outcomes reported as per trial protocol.
Other bias	Low risk	None identified.

Carmona 2011.

Study characteristics
Methods	Design: RCT Randomisation method: not stated Power calculation: not stated
Participants	Setting: tertiary care centre, Barcelona, Spain Number randomised: 38 women to each arm Inclusion criteria Age 18–40 years Unilateral or bilateral endometrioma ≥ to 3cm in diameter Exclusion criteria Previous pelvic surgery History of cancer Suspected malignancy Presurgical suspicion or evidence of deep endometriosis Presurgical suspicion or evidence of premature ovarian failure Use of oestrogen suppressive drugs, including oral contraceptives, GnRH agonists, progestins, or danazol in the preceding 6 months
Interventions	Laparoscopic excision of endometrioma versus drainage and coagulation of endometrioma
Outcomes	Recurrence of endometrioma Time to recurrence
Notes	No additional information provided by primary author.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Simple randomisation by computer‐generated randomisation list.
Allocation concealment (selection bias)	Low risk	Participants and surgeon unaware of allocation prior to surgery. Concealment of treatment allocation achieved with the use of sealed opaque envelopes, each containing a unique study number and prepared independently by a secretary. Envelopes were opened at diagnosis.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and surgeons were aware of allocation; unclear if sonographers were blinded to treatment.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	The same sonographer/investigators performed the ultrasounds, but unclear if they were blinded to the intervention.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data; however, 9/45 women in the excision group and 7/45 women in the ablation group were lost to follow‐up.
Selective reporting (reporting bias)	Low risk	All prespecified outcomes were reported.
Other bias	Low risk	No other sources of bias identified.

Fulop 2006.

Study characteristics
Methods	Design: 2‐arm RCT Randomisation method: not stated Power calculation: not stated
Participants	Setting: Budapest, Hungary Number randomised: 104 Typical endometriotic symptoms Endometrioma > 3 cm in diameter Exclusion criteria: not reported
Interventions	Stripping of the endometrioma wall (54 women) versus fenestration and ablation of the cyst wall (50 women
Outcomes	Rate of endometrioma recurrence Requirement for further surgery Recurrence rate of the symptoms of dysmenorrhoea Recurrence rate of the symptoms of dyspareunia Recurrence rate of the symptoms of pelvic pain
Notes	Study dates, funding sources, and declarations of interest not reported. In May 2020, we contacted the study authors requesting information regarding the randomisation process and numbers of women completing follow‐up, but received no reply.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "divided into two randomized groups". Comment: insufficient information.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not reported.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No withdrawals reported, but denominators not given for outcome data so unclear how many women provided data.
Selective reporting (reporting bias)	Unclear risk	No protocol available.
Other bias	Low risk	No other sources of bias identified.

Giampaolino 2015.

Study characteristics
Methods	Design: Prospective RCT Randomisation method: not stated Power calculation: not stated
Participants	Setting: tertiary centre in Naples, Italy. Number randomised: 64 (38 in each group) Inclusion criteria Age 22–38 years Unilateral ovarian endometrioma ≥ 3 cm in diameter Exclusion criteria Evidence of premature ovarian failure, Previous ovarian surgery Autoimmune diseases Multilocular cysts Use of drugs affecting ovarian function within the last 6 months Endocrine diseases and pregnancy
Interventions	Excision of the endometrioma versus drainage and coagulation of the endometrioma
Outcomes	Decrease in serum AMH levels Decrease in AFC
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were adequately randomised.
Allocation concealment (selection bias)	Low risk	Allocation concealment by way of opaque sealed envelopes ensured researchers were blinded to allocated treatment. Surgeons were not aware of allocation prior to surgery, but aware at the time of treatment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and surgeons were aware of allocation; unclear if sonographers were blinded to treatment.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	AMH levels are objective and unlikely to be affected by bias from blinding.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No missing outcome data, although 8/30 women in the ablation group were lost to follow‐up.
Selective reporting (reporting bias)	Unclear risk	All outcomes prespecified in the methods section of the paper were reported, but no protocol available.
Other bias	Low risk	No other source of bias identified.

Munrós 2019.

Study characteristics
Methods	Design: RCT Randomisation method: computer randomisation Power calculation: not stated
Participants	Setting: tertiary care hospital Number randomised: 30 (15 per group) Inclusion criteria Age 18–40 years Unilateral symptomatic endometrioma ≥ 3 cm in diameter Exclusion criteria Previous pelvic surgery for endometriosis History of cancer Suspected malignancy Presurgical suspicion or evidence of deep endometriosis Presurgical suspicion of evidence of premature ovarian failure Use of oestrogen suppressive drugs, including oral contraceptives, GnRH‐agonists, progestins, or danazol in the preceding 3 months
Interventions	Excision of the endometrioma versus drainage and CO2 laser vaporisation of the endometrioma
Outcomes	Total microparticle level
Notes	Dates of study: January 2015 and July 2016 Funding sources: "This work was supported by a Premi Fi de Residencia Emili Letang 2015 grant from the Hospital Clinic of Barcelona and by a research grant from Lumenis." Declarations of interest: "The authors declare that they have no conflicts of interest."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Simple randomisation through a computer‐generated randomisation list.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome assessor blinded, and the same experienced operator performed all assays.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only one participant withdrew, for reasons unrelated to the intervention.
Selective reporting (reporting bias)	Low risk	Outcomes seem to be reported in full.
Other bias	Low risk	Nothing to indicate any other source of bias.

Pados 2009.

Study characteristics
Methods	Design: RCT Randomisation method: opaque envelopes Power calculation: not stated
Participants	Setting: tertiary care hospital, Greece Number randomised: 20 Inclusion criteria Age 22–40 years Endometrioma ≥ 3 cm in diameter Exclusion criteria Pregnancy BMI > 30
Interventions	Laparoscopic stripping (cystectomy) of ovarian endometrioma versus 3‐stage procedure (drainage of cyst during laparoscopy, GnRh analogue for 12 weeks, ablation with laser)
Outcomes	Ovarian volumes and vascularisation measured as pulsatility and resistance indexes
Notes	This was the same group of patients reported in Tsolakidis 2010; therefore, we took care not to report the same outcomes/results twice.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Randomly allocated, but not computer generated.
Allocation concealment (selection bias)	Low risk	Participants and surgeons unaware of allocation prior to surgery. Opaque envelopes were used to allocate each group.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Surgeons and participants were not blinded to the procedure. Unclear if sonographers measuring outcomes were blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	The same operator performing the ultrasounds also performed the surgeries, and there is a high potential for bias, particularly with measuring a subjective outcome such as AFC.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Low risk	All prespecified outcomes were reported; this was confirmed with a study author.
Other bias	Low risk	No other sources of bias identified.

Salem 2013.

Study characteristics
Methods	Design: RCT Randomisation method: closed envelopes Power calculation: not stated
Participants	Setting: tertiary care hospital in Egypt Number randomised: 100 Inclusion criteria Age 18–35 years Unilateral or bilateral endometrioma and recent ultrasound showing endometrioma ≥ 5 cm Exclusion criteria High basal FSH Suspicion of malignancy Previous ovarian surgery PCOS and endocrine disease affecting ovarian reserve
Interventions	Laparoscopic stripping (cystectomy) versus coagulation of endometriotic cyst with bipolar diathermy/ablation
Outcomes	Decrease in AMH and AFC Decrease in ovarian volume
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Random allocation by closed envelopes. No computer randomisation. Method of sequence generation is unclear.
Allocation concealment (selection bias)	Unclear risk	Allocation concealment is unclear.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and surgeons were aware of allocation.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unclear if sonographers were blinded to the type of surgery.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	7/100 participants lost to follow up. Handling of patient data thereafter unclear.
Selective reporting (reporting bias)	Unclear risk	All outcomes prespecified in separate protocol were reported.
Other bias	Low risk	No other sources of bias identified.

Var 2011.

Study characteristics
Methods	Design: RCT Randomisation method: computer randomisation Power calculation: not stated
Participants	Setting: Tertiary care hospital, Ankara, Turkey Number randomised: 48 Inclusion criteria Infertility Age 20–35 years Bilateral endometrioma 4–6 cm in diameter Exclusion criteria Previous ovarian surgery Use of hormone suppressing therapy for endometriosis
Interventions	Laparoscopic cystectomy of endometrioma (on one side) and coagulation with bipolar (on other side)
Outcomes	Ovarian reserve as determined by AFC and ovarian volume, before and after performing coagulation and cystectomy Response to controlled ovarian hyperstimulation, measured by number of follicles > 14 mm (dominant follicle) and number of retrieved oocytes Clinical pregnancy rates after IVF (fetal heart beat demonstrated by sonography)
Notes	We contacted the study authors for further information. The clinical pregnancy rate reported cannot be used to compare cystectomy versus coagulation as both were performed in all women.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Coagulation and cystectomy were performed on either side of participants for their endometriomas using cross randomisation. Method of randomisation was inadequately described.
Allocation concealment (selection bias)	Unclear risk	All women received cystectomy or coagulation on one endometrioma and the opposite treatment on the contralateral ovary. Treatment allocation to either ovary was randomly assigned.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Participants and surgeons were aware of allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The same radiologist performed ultrasound assessment pre‐ and postoperatively, and they were blinded to the type of surgery performed.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	11/48 women conceived spontaneously. Only 37 patients who had IVF were included in the review.
Selective reporting (reporting bias)	Unclear risk	No protocol available to confirm whether all prespecified outcomes were reported.
Other bias	Low risk	This study randomised each ovary to either cystectomy or ablation in women with bilateral endometrioma. Therefore, pregnancy‐related outcomes such as clinical pregnancy could not be compared for each surgical technique. We could only comment on outcomes specific to the ovary, such as AFC.

AFC: antral follicle count; AMH: anti‐Müllerian hormone; FSH: follicle‐stimulating hormone; IVF: in‐vitro fertilisation; PCOS: polycystic ovary syndrome; RCT: randomised controlled trial.

Characteristics of excluded studies [ordered by study ID]

Study	Reason for exclusion
Dan 2013	Systematic review.
Detorakis 2014	Ineligible intervention.
Fayez 1991	Inadequate randomisation.
Georgievska 2015	Non‐randomised.
Ghasemi Tehrani 2022	Ineligible intervention.
Hemmings 1998	Non‐randomised.
Muzii 2016	Both stripping (cystectomy) and ablation were performed on the same ovary.
NCT02754648	Dataset did not reach completion and publication. Results could not be verified as no investigator is listed.
Roman 2011	Retrospective 'before and after' comparative study. Not randomised.
Saha 2020	Ineligible comparison.
Saito 2014	Prospective study not appropriately randomised. Vaporisation with bipolar current was performed in nulligravid women and cystectomy in those who had a child.
Saleh 1999	Retrospective study.
Sweed 2019	Comparison of cyst excision versus cyst de‐roofing (not ablation).

Characteristics of studies awaiting classification [ordered by study ID]

Alborzi 2004.

Methods	Design: RCT Randomisation method: computer randomisation Power calculation: not stated
Participants	Setting: infertility and gynaecologic endoscopy units of 2 medical university hospitals in Shiraz, Iran Number randomised: 100 Inclusion criteria Endometrioma ≥ 3 cm in diameter Exclusion criteria Previous surgery for endometriosis Use of hormone suppressing therapy in the last 6 months
Interventions	Excision of the endometrioma (52 women) versus drainage and ablation of the endometrioma (48 women). Histological examination of the ovarian cyst confirmed the presence of endometriosis in all cases.
Outcomes	Recurrence of endometrioma Recurrence of symptoms of pain and dysmenorrhoea Need for reintervention Spontaneous conception at 12 months after surgery (definition of pregnancy not provided)
Notes	Additional information provided by first author. Although this was a multicentre study, the surgery was performed by the same surgeon in separate sites. Awaiting classification pending further confirmation of study details.

Alborzi 2007.

Methods	Design: RCT Randomisation method: computer randomisation Power calculation: not stated
Participants	Setting: infertility and gynaecologic endoscopy units of 2 medical university hospitals in Shiraz, Iran Number randomised: 65 Inclusion criteria Unilateral or bilateral endometrioma ≥ 3 cm in diameter Exclusion criteria Previous surgery for endometriosis Previous fertility treatments
Interventions	Excision of the endometrioma versus drainage and ablation of the endometrioma
Outcomes	Follicular response in the treated ovary Pregnancy rates after two cycles of controlled ovarian stimulation
Notes	Additional information provided by first author. Some women had bilateral endometriomas and each endometrioma was treated differently to assess the effect of response to stimulation. These women are not eligible for inclusion in the review. Awaiting classification pending further confirmation of study details.

Rius 2020.

Methods	Design: RCT Randomisation method: computer‐generated sequence; concealed in an opaque, sealed envelope Power calculation: not stated
Participants	Setting: Hospital Clínic of Barcelona, between January 2017 and December 2017 Number randomised: 16 Inclusion criteria Age 18–45 years Bilateral ovarian endometriomas Exclusion criteria: none listed
Interventions	Cystectomy versus drainage and laser coagulation of the inner lining
Outcomes	AFC Ovarian volume Recurrence Pregnancy
Notes	Awaiting classification pending confirmation of methods and results details by trial authors.

Shaltout 2019.

Methods	Design: RCT Method of randomisation: computer‐generated random numbers Power calculation: not stated
Participants	Setting: Cairo, Egypt Number randomised: 215 Inclusion criteria Age 20–35 years Candidate for conservative laparoscopic treatment of ovarian endometriomas (either by drainage or cyst wall excision) Endometriosis‐related clinical manifestations (infertility, pelvic pain, or pelvic mass) Unilateral and unilocular endometrioma (≥ 5 cm) Rapidly growing endometrioma Good ovarian reserve (AMH > 1 ng/mL and AFC > 4) Exclusion criteria Recurrent and bilateral cases Unfit for surgery Chronic diseases (e.g. cardiac disease or diabetes) Contraindications for laparoscopic surgery (excessive anterior abdominal wall scarring)
Interventions	Group D (drainage only; 53 women): laparoscopic fenestration and electrocautery of the endometrioma cyst wall Group C (cystectomy only; 54 women): laparoscopic excision of the endometrioma cyst wall Group DS (drainage & Surgicel; 55 women): laparoscopic fenestration of the endometrioma cyst wall followed by insertion of 4–8 pieces of Surgicel inside the cyst cavity Group CS (cystectomy & Surgicel; 50 women): laparoscopic excision of the endometrioma cyst wall followed by insertion of 4–8 pieces of Surgicel inside the remaining ovarian tissues Groups C and D are eligible interventions for the review; groups DS and CS are ineligible.
Outcomes	Recurrence at 24 months Pregnancy rate at 24 months Adverse events
Notes	Dates of study: October 2016–January 2019 Authors contacted for clarification of study details including follow‐up times.

AFC: antral follicular count; AMH: anti‐Müllerian hormone; RCT: randomised controlled trial:

Characteristics of ongoing studies [ordered by study ID]

NCT03615352.

Study name	Impact of laparoscopic ovarian cystectomy versus aspiration and coagulation on ovarian reserve and pelvic pain in cases of ovarian endometrioma
Methods	Participant‐blinded RCT
Participants	Number of participants: 92 women Inclusion criteria Age 20–40 years Ultrasound diagnosis of unilateral ovarian endometrioma ≥ 3 cm Exclusion criteria Previous ovarian surgery Endocrinological diseases affecting ovarian reserve (e.g. diabetes mellitus, hypothyroidism) PCOS Suspicion of ovarian malignancy by ultrasound Other pelvic pathology (e.g. uterine fibroid, pelvic inflammatory disease) Basal FSH >10 mIU/mL
Interventions	Laparoscopic ovarian cystectomy versus laparoscopic ovarian endometrioma aspiration and coagulation
Outcomes	AMH at 3 months after laparoscopy AFC at 3 months after laparoscopy Chronic pelvic pain measured by VAS at 3 months after laparoscopy
Starting date	1 January 2018 Expected completion date 1 October 2018
Contact information	Principal investigator: Mohammed Zayed Abd Elaziz, MD; Cairo University No contact information given
Notes

AFC: antral follicular count; AMH: anti‐Müllerian hormone; FSH: follicle‐stimulating hormone; PCOS: polycystic ovary syndrome; RCT: randomised controlled trial; VAS: visual analogue scale.

Differences between protocol and review

In the 2024 update:

• Where spontaneous pregnancy was defined by the studies, it referred to clinical pregnancy in at least one registered gestation sac or fetal pole with embryonic heartbeat on ultrasound. Live birth rate data were not reported in the studies.

• We changed the definition of endometrioma to include those larger than or equal to 3 cm in diameter, as surgery for pain or fertility is generally not considered for smaller endometriomas.

• We split the outcome 'ovarian function' into two separate outcomes ('ovarian reserve' and 'ovarian response to stimulation') to provide more information about the effect of surgery on fertility‐related outcomes. There have been advances in ovarian reserve testing since the last review version, and it is a valuable tool for determining a woman's prognosis from assisted reproductive treatment (ART). It is expected that surgical removal of an endometrioma could damage the ovarian cortex and lead to a decline in ovarian reserve. The ideal surgical technique for removal of endometrioma should minimise decline in ovarian reserve as measured by anti‐Müllerian hormone (AMH), antral follicle count, or ovarian volume.

• One new study compared the modified three‐step drainage and ablation procedure and has been introduced as a new subgroup.

• We removed the outcome 'quality of life'. No studies identified in the original review reported this outcome, and in subsequent versions of the review we wanted to focus on pain‐ and fertility‐related outcomes as they are most relevant when contemplating surgery.

• We changed the primary outcomes to focus on pelvic pain and adverse events (including surgical complications and conversion to laparotomy).

• Recurrence of endometrioma and requirement for further endometrioma surgery are now separate secondary outcomes rather than being included in adverse events.

• We identified seven clinically important outcomes and assessed the certainty of evidence for those outcomes using the GRADE approach. We presented the certainty of evidence in a summary of findings table.

• We revised the background and methods to current Cochrane standards.

Contributions of authors

RK: protocol rewriting, study selection, data extraction and analysis, review writing and updating.
RMcD: study selection, data extraction and analysis.
FS: study selection, data extraction, extensive review editing and updating.
RH: conception and initiation of initial protocol; writing of original protocol; development of background, initial objectives, selection criteria, methods, and search strategy; writing of previous reviews.
MH: contribution to initial objectives, contribution to writing of initial protocol and development of background, selection criteria, methods, search strategy. 
CF: contribution to initial protocol; writing of original protocol; development of background, initial objectives, selection criteria, methods, and search strategy; writing of previous reviews.

Sources of support

Internal sources

• None, Other

  None

External sources

• None, Other

  None

Declarations of interest

RK has no conflicts to declare.
RMcD has declared an employment contract with King Edward Memorial Hospital, Western Australia.
FS contributed to the review in her role as Network Support Fellow to the former Cochrane Children & Families Network. She took no part in any editorial decisions relating to this review.
RJH has no conflicts to declare.
MH has no conflicts to declare.
CF has no conflicts to declare.

New search for studies and content updated (no change to conclusions)