Abstract
Background
Surgical bleeding complications typically occur a few hours or days after the operation. Due to their rarity, late-onset bleeding complications are seldom discussed in the literature. Mastectomy is a common procedure, which is often associated with the need for repeated seroma aspirations. Although seroma aspirations have also been associated with complications, the area remains insufficiently studied. This study aimed to investigate the risk of late bleeding complications after mastectomy, especially those associated with seroma aspiration.
Methods
Data from all patients undergoing simple mastectomy with or without axillary surgery for breast cancer between 2010 and 2022 at a single university hospital were collected. Medical records were reviewed for major bleeding complications and predisposing factors, especially the use of antithrombotic medications.
Results
In total, 2,620 patients with 2,710 mastectomies were included in the study. Forty-five patients (1.7%) suffered a major bleeding complication. Twenty-four complications (53%) occurred after the first postoperative week; most (88%, 21/24) being preceded by a seroma aspiration. The median time from mastectomy to seroma aspiration-associated bleeding complication was 76 days (range 11–536 days). Upon arrival for treatment, 691 (26%) patients were taking antithrombotic medications. The risk for major bleeding complications related to seroma aspiration was 1.9% (13/691) and 0.4% (8/1929) in patients receiving and not receiving antithrombotic medications, respectively (p < 0.0001).
Conclusion
A significant proportion of major post-mastectomy bleeding complications occur late and are associated with seroma aspiration, particularly in patients receiving antithrombotic therapy. The indication, technique, and setting of seroma aspiration in these high-risk patients should be carefully considered.
Keywords: Mastectomy, Seroma, Aspiration, Puncture, Antithrombotic medication, Hematoma, Bleeding complications
Introduction
Breast cancer is the most common malignancy among women worldwide and its risk increases with age [1]. Older age is associated with conditions requiring antithrombotic medications, which predispose the patients to bleeding complications [2–4]. Additionally, elderly patients often undergo mastectomy, for example to avoid postoperative radiotherapy (RT) or the risk of reoperation after breast-conserving surgery (BCS), although mastectomy poses a higher risk for complications compared to BCS [5, 6].
One of the most common complications after breast cancer surgery is postoperative bleeding, which is usually reported to occur within hours or days after the procedure [7–9]. Surgical research usually reports complications occurring within the first 30 postoperative days, which is seemingly sufficient to cover bleeding complications [10]. However, patients undergoing mastectomy often develop subsequent seroma requiring aspirations [11]. The aspiration is performed through skin flaps containing blood vessels, which may be injured in the procedure. Although the risk of major complications may appear negligible, the mastectomy cavity is large, allowing for a large volume of bleeding. Especially in patients on antithrombotic medications, such complication may lead to significant bleeding that jeopardizes hemodynamic stability [12]. However, no prior study has systematically quantified the risk of major bleeding after seroma aspiration post mastectomy. A search performed in PubMed database (performed on February 12th, 2025, utilizing terms [“mastectomy” OR “breast surgery”] AND “seroma” AND [“puncture” OR “aspiration” or “drainage”] AND [“hematoma” OR “bleeding”]) produced only studies mentioning, but none investigating the subject [13].
To study this little-known topic and assess the risk for major bleeding complications related to seroma aspiration, we reviewed the data of all mastectomy patients treated at a single tertiary university hospital from 2010 to 2022. The primary outcome of this study was major postoperative bleeding after mastectomy. Early and late bleeding were analyzed as temporal stratifications of the primary endpoint, and bleeding events related to seroma aspiration were evaluated as a predefined subset analysis.
Materials and methods
Study population
Data for all patients who underwent simple mastectomy, defined as removal of the entire breast tissue, with or without axillary surgery, for breast cancer or ductal carcinoma in situ (DCIS) at a single tertiary hospital from 2010 to 2022 were collected from the Auria Clinical Informatics Register. Patients who underwent breast reconstruction at the time of surgery or those undergoing prophylactic mastectomy were not included.
Surgical procedure
Mastectomy was mainly performed with energy-based instruments, based on the surgeon’s preference. Most surgeons preferred ultrasonic instruments, namely SonoSurg® (Olympus Corporation, Tokyo, Japan), ThunderBeat® (Olympus Corporation, Tokyo, Japan), and Harmonic Focus® (Ethicon Inc., Cincinnati, OH, USA) and those surgeons not preferring ultrasonic instrument utilized predominantly an electrothermal bipolar technique based LigaSure Vessel Sealing System (Covidien Valleylab, Boulder, CO, USA).
Skin flaps were prepared to 5–10 mm in thickness. Axillary lymph node dissection (ALND) was performed if lymph node metastasis was biopsy-proven before the operation or the metastasis was detected in frozen section study of sentinel lymph node biopsy (SLNB). SLNB was performed using the triple technique (preoperative 99mTc isotope injection, lymphoscintigraphy, and intraoperative blue dye injection). Frozen section analysis was performed on all sentinel lymph nodes until 2018, and only in selected cases thereafter, in accordance with the updated treatment guidelines.
The perioperative management of antithrombotic therapy varied by surgeon and by medication. Information on whether an antithrombotic agent affecting coagulation was discontinued or continued across surgery was recorded.
A single drain was placed, or two drains in bilateral mastectomies, each kept in place until daily exudate decreased to less than 80 ml, or for a maximum of seven days. For wound closure, the subdermal tissue was approximated using absorbable sutures, and the skin was closed with a continuous intracutaneous absorbable suture.
Postoperative care
Patients had a postoperative follow-up appointment approximately three weeks after surgery. In cases of postoperative seroma formation, the patients were usually referred to primary health care for seroma aspirations. According to local practice, seroma aspiration is performed with the patient in the supine position, accessing the seroma cavity from its lateral aspect, typically using an 18-gauge, 40-mm needle. Ultrasound is not routinely used in case of clinically evident seroma. In case of major complications, the patients were referred to public specialized healthcare which in Finland is almost exclusively responsible for the management of such complications. The study was conducted at a tertiary university hospital managing all major surgical complications in the district, indicating that the complications that occurred are included in the data with few exceptions.
Definitions
The primary outcome of the study was the occurrence of a major postoperative bleeding complication following mastectomy. A standardized definition for major bleeding complication was used [14]. Effectively, the criteria were fulfilled if the bleeding complication required reoperation or resulted in a decrease in hemoglobin level of at least 20 g/l.
In the absence of standardized criteria, bleeding complications were considered early if they were detected within the first postoperative week and late if detected thereafter. The temporal classification was applied to describe the timing of bleeding complications and to enable comparison between early and late complication events.
Because many seroma aspirations were performed in primary care and were incompletely documented, the number of individual aspiration episodes could not be reliably determined. Therefore, bleeding risk was estimated per mastectomy rather than per aspiration episode.
Data collection
For each patient, age, body-mass index (BMI), ASA physical status classification (American Society of Anesthesiologists), and use of antithrombotic medication were recorded. The following data were collected in relation to mastectomy procedure: performing surgeon, performed axillary surgery, duration of the surgery, laterality of the operation and utilized surgical instrument. Information on all admissions to emergency department and to specialized health care related to breast cancer, performed surgical procedures, patient records with the complication diagnosis code (T81 in ICD-10), laboratory tests associated with bleeding complications (hemoglobin, hematocrit, and blood transfusions) was retrieved from the database and the accuracy of the data was verified from the electronic patient records. Patient records were reviewed throughout the entire study period to ensure that all events, including late events, were captured.
Statistical analysis
The data were analysed using JMP 17 Pro (SAS Institute, Cary, North Carolina, USA) analysis software. For patients’ age and BMI, median and interquartile ranges were defined. Frequency tables for bleeding complications were generated. Univariable logistic regression analysis was used to identify predictors of postoperative bleeding complications, with early and late bleeding complications as the dependent variable in separate analyses. All patient and surgery-related variables described in the Data collection section were included in the analysis. The results are reported as odds ratios with 95% confidence intervals. A chi-square test was used for categorical variables, and a two-sample t-test or Wilcoxon rank-sum test was used for normally and non-normally distributed continuous variables, respectively.
The research protocol of the study was approved by the Hospital District of Southwest Finland (T537/2022). Data were analysed in a pseudonymized manner in accordance with institutional and national data protection regulations. This study is reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines [15].
Results
In total, 2,620 patients were included in the study. Bilateral mastectomy was performed in 93 patients, totalling 2,713 breasts at risk (Table 1). Operations were performed by 38 surgeons with varying experience on breast cancer surgery. Overall, 14 surgeons performed more than 50 mastectomies.
Table 1.
Patient characteristics and information of antithrombotic medications. Values are n (%) unless otherwise indicated. (IQR= interquartile range, BMI = body-mass index, ASA = American Society of Anesthesiologists, DCIS = ductal carcinoma in situ, ALND = axillary lymph node dissection, SLNB = sentinel lymph node biopsy, BCS = breast conserving surgery *percentage of antithrombotic medications)
| 2620 patients | |
|---|---|
| Age (years), median (IQR) | 67.9 (55.8–79.1) |
| BMI (kg/m2), median (IQR) | 26.1 (22.9–30.1) |
| ASA Classification | |
| ASA Class 1 | 354 (14%) |
| ASA Class 2 | 1155 (44%) |
| ASA Class 3 | 1005 (38%) |
| ASA Class 4 | 98 (3.7%) |
| Information missing | 8 (0.3%) |
| Antithrombotic medication | 691 (26%) |
| -Acetylsalicylic acid | 309 (45%)* |
| -Other antiplatelets | 38 (5.5%)* |
| -Warfarin | 166 (24%)* |
| -Direct oral anticoagulants | 106 (15%)* |
| -Combination therapy (usually aspirin and dipyridamole) | 20 (2.9%) * |
| -Low-molecular-weight heparin | 29 (4.2%)* |
| Bilateral mastectomy | 93 (3.4%) |
| Mastectomy performed as reoperation after BCS | 279 (11%) |
| Patients with invasive breast cancer (in either breast) | 2443 (93%) |
| Patients with DCIS (no invasive cancer in either breast) | 177 (6.8%) |
| Axillary surgery | |
| ALND | 1437 (54%) |
| SLNB | 1047 (40%) |
| None | 136 (5.1%) |
| Duration of surgery (min, IQR) | 102 (80–120) |
During the entire study period, 45 patients (1.7%, 95% CI 1.3%−2.3%) suffered a major bleeding complication (Fig. 1). Three patients were managed without surgical intervention and 42 underwent surgery. One patient presenting with a bleeding complication had no comparison value for hemoglobin and did not undergo reoperation, so the patient did not meet the criteria for major bleeding complication. As shown in the Fig. 1, less than half of the patients (47%, 21/45) suffered the complication during the first postoperative week, with the majority (76%, 16/21) of these occurring within 24 h of the initial operation.
Fig. 1.
Temporal distribution of major bleeding complications after mastectomy
In the statistical analysis, the risk factors for early (Table 2) and late bleeding complications (Table 3) differed.
Table 2.
Comparison of patients suffering early postoperative bleeding complications to the patients not suffering the complication. Values are n (%) unless otherwise indicated. #Odds ratio could not be estimated due to zero events. (IQR= interquartile range, BMI = body-mass index, ASA = American Society of Anesthesiologists, ALND = axillary lymph node dissection, SLNB = sentinel lymph node, CI = confidence interval)
| Patients with early bleeding complication | Yes (n = 21) | No (n = 2599) | p-value | Odds Ratio (95% CI) |
|---|---|---|---|---|
| Age (years), median (IQR) | 67.2 (63.0–82.9.0.9) | 67.9 (55.8–86.1) | p = 0.31 | 1.01 (0.98–1.04) per unit |
| BMI (kg/m2), median (IQR) | 25.1 (22.9–27.1) | 26.1 (22.9–30.1) | p = 0.21 | 0.96 (0.87–1.04) per unit |
| ASA Classification | ||||
| ASA Class 1 | 2 (9.5%) | 352 (14%) | p = 0.81 | reference |
| ASA Class 2 | 8 (38%) | 1147 (21%) | 1.23 (0.26–5.81) | |
| ASA Class 3 | 10 (48%) | 995 (38%) | 1.77 (0.39–8.11) | |
| ASA Class 4 | 1 (4.8%) | 97 (3.7%) | 1.81 (0.16–20.2) | |
| Antithrombotic medication | 9 (43%) | 682 (26%) | p = 0.09 | 2.10 (0.88–5.02) |
| No antithrombotic medication | 12 (57%) | 1917 (74%) | reference | |
| Antithrombotic medication discontinued perioperatively | ||||
| Yes | 4 (1.3%) | 283 (99%) | p = 0.93 | 1.10 (0.27–4.20) |
| No | 5 (1.3%) | 390 (99%) | reference | |
| Not recorded | 0 | 10 | # | |
| Axillary surgery | ||||
| ALND | 12 (57%) | 1425 (55%) | p = 0.59 | 0.94 (0.37–2.38) |
| SLNB | 9 (43%) | 108 (40%) | reference | |
| None | 0 (0%) | 136 (5.2%) | # | |
| Bilateral mastectomy | 3 (14%) | 90 (3.5%) | p = 0.02* | 4.64 (1.34–16.1) |
| Unilateral mastectomy | 18 (86%) | 2509 (97%) | reference | |
| Ultrasonic instrument | 10 (48%) | 2205 (85%) | p < 0.001* | 0.16 (0.07–0.39) |
| Any other instrument | 11 (52%) | 394 (15%) | reference | |
| Duration of surgery (min, IQR) | 93 (78–129) | 102 (80–120) | p = 0.96 | 1.00 (0.99–1.01) per unit |
Table 3.
Comparison of patients suffering late postoperative bleeding complications to the patients not suffering the complication. Values are n (%) unless otherwise indicated. #Odds ratio could not be estimated due to zero events. (IQR= interquartile range, BMI = body-mass index, ASA = American Society of Anesthesiologists, ALND = axillary lymph node dissection, SLNB = sentinel lymph node, CI = confidence interval)
| Patients with late bleeding complication | Yes (n = 24) | No (n = 2596) | p-value | Odds Ratio (95% CI) |
|---|---|---|---|---|
| Age (years), median (IQR) | 75.6 (64.6–82.4) | 67.8 (55.8–79.1) | p = 0.007* | 1.04 (1.01–1.07) per year |
| BMI (kg/m2), median (IQR) | 26.8 (22.2–31.8) | 26.1 (22.9–30.1) | p = 0.64 | 1.02 (0.95–1.09) per unit |
| ASA Classification | ||||
| ASA Class 1 | 3 (13%) | 351 (14%) | p = 0.02* | reference |
| ASA Class 2 | 5 (21%) | 1150 (44%) | 0.48 (0.11–2.03) | |
| ASA Class 3 | 13 (54%) | 992 (38%) | 1.41 (0.39–5.09) | |
| ASA Class 4 | 3 (13%) | 95 (13%) | 3.56 (0.69–18.5) | |
| Antithrombotic medication | 13 (54%) | 678 (26%) | p = 0.002* | 3.34 (1.49–7.50) |
| No antithrombotic medication | 11 (46%) | 1918 (74%) | reference | |
| Antithrombotic medication discontinued perioperatively | ||||
| Yes | 9 (3.1%) | 278 (97%) | p = 0.11 | 3.16 (1.02–11.8) |
| No | 4 (1.0%) | 391 (99%) | reference | |
| Not recorded | 0 | 10 (100%) | # | |
| Axillary surgery | ||||
| ALND | 16 (67%) | 1421 (55%) | p = 0.77 | 1.31 (0.17–10.1) |
| SLNB | 7 (29%) | 1040 (40%) | 0.94 (0.11–7.67) | |
| None | 1 (4.2%) | 135 (5.2%) | reference | |
| Bilateral mastectomy | 2 (8.3%) | 91 (3.5%) | p = 0.20 | 2.50 (0.58–10.8) |
| Unilateral mastectomy | reference | |||
| Ultrasonic instrument | 21 (88%) | 2194 (85%) | p = 0.68 | 1.28 (0.38–4.32) |
| Any other instrument | 3 (13%) | 402 (15%) | reference | |
| Duration of surgery (min, IQR) | 98 (85–113) | 102 (79–120) | p = 0.64 | 1.00 (0.98–1.00.98.00) |
Of the 24 bleeding complications that occurred after the first seven postoperative days, 21 (88%) were explicitly recorded as resulting from a preceding seroma aspiration. In two of the three patients in whom the bleeding complication could not be directly attributed to a preceding seroma aspiration, both had a history of prior seroma aspirations, but the hematoma was detected as an asymptomatic finding during routine follow-up. In these patients the hematoma was followed at first, but both ultimately required surgical treatment. The reoperations in these two patients were performed on postoperative days 158 and 2044, respectively.
The third patient suffered a postoperative surgical site infection. The patient’s wound was partially opened as part of the treatment for the infection, which caused major bleeding that necessitated surgical intervention, performed on the 13th postoperative day.
None of these three patients were receiving antithrombotic medications.
In the remaining 21 patients, the bleeding complication was explicitly attributable to a preceding seroma aspiration (Table 4). Typically, these complications occurred more often months rather than weeks after the operation (median 76 days, range 11–536 days), only three of them occurring within the first 30 postoperative days. Most of these patients (62%, 13/21) were receiving antithrombotic medications at the time of the bleeding complication, and the risk for bleeding complication substantially higher in these patients (13/691, 1.9%; 95% CI 1.1–3.2%) than in patients without such medications (8/1929, 0.4%; 95% CI 0.2–0.8%) corresponding to an absolute risk difference of 1.5% points (p < 0.0001).
Table 4.
Characteristics of patients suffering from seroma aspiration-related bleeding complication. (ALND = axillary lymph node dissection, SLNB = sentinel lymph node biopsy)
| Time from primary operation (days) | Patients age (years) | Body-Mass Index (kg/m2) | Bilateral Mastectomy | Axillary operation | Antithrombotic medication | Urgency classification of complication surgery | Hemoglobin level (g/l) at the time of diagnosis |
|---|---|---|---|---|---|---|---|
| 11 | 57 | 21.2 | No | ALND | no | Emergency | 77 |
| 13 | 91 | 25.0 | Yes | ALND (Bilateral) | enoxaparin | Emergency | 73 |
| 20 | 70 | 28.6 | No | SLNB | warfarin | Urgent | 86 |
| 30 | 78 | 20.2 | No | ALND | no | Urgent | 82 |
| 49 | 64 | 24.2 | No | ALND | acetylsalicylic acid | Urgent | - |
| 52 | 91 | 28.0 | No | ALND | dabigatran | Urgent | 93 |
| 54 | 56 | 21.6 | No | ALND | no | Urgent | - |
| 55 | 82 | 34.9 | No | ALND | combination of acetylsalicylic acid and clopidogrel | Emergency | 85 |
| 57 | 69 | 42.8 | Yes | ALND (Bilateral) | rivaroxaban | Urgent | 113 |
| 69 | 81 | 28.5 | No | ALND | acetylsalicylic acid | Urgent | - |
| 76 | 89 | 32.4 | No | ALND | apixaban | No surgery | 90 |
| 89 | 81 | 30.9 | No | ALND | no | Urgent | 96 |
| 110 | 69 | 20.1 | No | None | no | Elective | - |
| 133 | 82 | 23.7 | No | SLNB | acetylsalicylic acid | Elective | 81 |
| 209 | 87 | 28.4 | No | SLNB | acetylsalicylic acid | Elective | 128 |
| 246 | 77 | 35.7 | No | ALND | no | Elective | 121 |
| 359 | 74 | 32.2 | No | ALND | no | Elective | 107 |
| 370 | 62 | 27.6 | No | SLNB | no | Elective | - |
| 425 | 66 | 21.7 | No | ALND | acetylsalicylic acid | Elective | 119 |
| 461 | 75 | 26.0 | No | SLNB | acetylsalicylic acid | Elective | 126 |
| 536 | 84 | 34.7 | No | ALND | rivaroxaban | Elective | 127 |
In detailed analysis, the complications related to seroma aspiration could be divided further into two distinct entities: In the twelve patients, whose bleeding complication was diagnosed within three months of the primary operation, the complication typically occurred shortly after the seroma aspiration, developed rapidly and required urgent reoperation. The volume of blood evacuated in reoperation was high (mean 480 ml, range 200–800 ml) and caused a significant drop in patients’ hemoglobin. Most patients did not have a comparison value for hemoglobin taken between the mastectomy and the bleeding complication, but the mean level hemoglobin measured within reoperation was 88 g/l (range 73–113 g/l), significantly lower than what would be expected in patients without complications.
In nine patients whose bleeding complication developed more than three months after surgery, conservative treatment was typically attempted initially, with a follow-up period of several days or weeks, before the decision to proceed to reoperation was made. The volume of hematoma evacuated in these patients was lesser (mean 244 ml, range 150–500 ml) and the hemoglobin levels were higher than in patients suffering an early bleeding complication. Actually, the hemoglobin levels in all but two patients undergoing reoperation remained within normal range, likely reflecting the slow progression of the hematoma and the body’s ability to compensate for gradual blood loss.
Discussion
To date, seroma aspiration-associated bleeding complications after breast surgery have received little attention. To our knowledge, this is the first published scientific study to provide a quantitative estimate of the incidence of such complications. The present study reveals that these complications constitute a relatively high proportion of all bleeding complications following mastectomy. Actually, the number of bleeding complications related to seroma aspiration was higher than the number of bleeding complications detected within 24 h after the surgery, which is the most typical time frame of surgical bleeding complications [10]. The risk for seroma aspiration-related bleeding complications was shown to be elevated especially in patients receiving antithrombotic medications compared to patients without such medications.
Timing of bleeding complications
Based on the results of this study, it can be observed that the timing of bleeding complications is clearly associated with their clinical presentation.
Approximately one third of bleeding complications occurred during the first postoperative day, which is consistent with previous literature [10]. Such bleeding events typically develop rapidly, and patients usually require urgent reoperation to control the bleeding.
Bleeding complications diagnosed within the first postoperative week rarely have any precipitating factor other than the surgery itself. Although this aspect was not specifically investigated in the present study, it may be speculated that this finding could be related to less pronounced or more slowly developing postoperative bleeding. In the case of mastectomy, smaller amounts of bleeding may go undiagnosed initially, which may be explained by the relatively large surgical cavity, such that only a substantial volume of bleeding becomes clinically apparent [12].
Bleeding complications occurring without an evident predisposing factor are rare after the first postoperative week. The most common cause of such bleeding is seroma aspiration. Based on the interpretation of the patient cohort in this study, it appears that bleeding episodes occurring after seroma aspiration within the first three months following surgery tend to be more severe than those occurring thereafter. This may be explained by the large size and continuity of the aspirated seroma cavity, which gradually decreases in size over time, and allows a larger volume of bleeding the earlier it develops after surgery.
Overall, it is noteworthy that bleeding complications associated with seroma aspiration developed considerably later than expected, with a median onset of 76 days after surgery. Surgical complications are conventionally recorded only within a limited postoperative follow-up period, for example 30 days, and as a result these bleeding complications fall outside the scope of outcomes captured in standard studies [10].
Currently, there are no well-established criteria in the existing literature for classifying postoperative bleeding complications as either early or late. The cut-off values used for timing of bleeding complications in the literature are variable and partly arbitrary [16]. The results of the present study may provide guidance in the context of mastectomy.
Risk factors for bleeding complications
The risk factors for early bleeding complications were bilateral surgery and used instrument - with ultrasonic instruments having the lowest risk for bleeding. It has previously been shown that the use of ultrasonic instruments is associated with a lower risk of bleeding compared with other surgical instruments [9].
The risk of late bleeding complications was higher in patients receiving antithrombotic medication than in those not receiving such medication. Higher ASA class and advanced age were also statistically associated with bleeding complications and were strongly correlated with the use of antithrombotic medication. Given the limited number of outcome events (n = 45), multivariable modeling was not performed, and the reported associations should therefore be considered exploratory and unadjusted for potential confounding. Consequently, causality cannot be inferred. Although antithrombotic medication may represent a clinically plausible contributing factor, age and ASA class likely reflect underlying comorbidity and treatment indication. These findings should therefore be interpreted with caution and considered hypothesis-generating. This interpretation would also be consistent with previous literature [17].
Clinical relevance of bleeding complications
Even infrequent bleeding events may have a significant impact on patient outcomes and healthcare utilization. They may necessitate reoperation, prolong hospital stay, increase the risk of infectious complications, and delay adjuvant oncologic treatments [18, 19]. As shown in the present study, early bleeding complications are associated with a significant decrease in hemoglobin level. Anemia and major surgical bleeding are known to predispose the patient to severe thromboembolic complications, such as stroke and myocardial infarction [20, 21]. A previous study has reported that 6% of patients with atrial fibrillation who experienced stroke while receiving antithrombotic medication had undergone surgical operation within the preceding 30 days [22]. The use of antithrombotic medications is associated with an increased risk of bleeding complications, as well as underlying conditions that elevate the risk of thromboembolic and ischemic complications [23, 24]. For these reasons, appropriate perioperative management of antithrombotic medication is of paramount importance.
Practical implications
This study demonstrated that postoperative seroma, and particularly seroma aspiration, is associated with an increased risk of bleeding complications requiring surgical intervention. The treatment and prevention of seroma is a long-term issue, and there is no clear solution that stands out as the best [25, 26]. This study adds another perspective to the discussion, emphasizing the need to find either an effective preventive measure or treatment for seroma formation. When considering seroma aspiration, it should be evaluated what volume of seroma justifies aspiration in terms of the risk–benefit balance, and whether reducing the needle size or using ultrasound guidance could decrease the risk of complications. In addition, performing the aspiration in specialized care by an experienced professional should be considered especially in high-risk patients, such as elderly individuals and those receiving antithrombotic medication.
We consider that the magnitude of the post-mastectomy bleeding risk warrants acknowledging when considering the surgical treatment in patients taking antithrombotic medications. It is recognized that mastectomy is associated with a substantially higher risk of postoperative seroma formation compared with BCS [27]. In our view, this study provides additional support for favoring BCS also in older patients with comorbidities.
Notably, the risk for early bleeding complications was not elevated in the patients who were taking antithrombotic medications. This results from the use of ultrasound instruments in mastectomy, as it has been previously demonstrated that these instruments reduce the risk of bleeding complications, regardless of the use of antithrombotic medications [9, 28]. This is particularly relevant, as interruption of antithrombotic medication is associated with an increased risk of surgery-related thromboembolic complications [29]. This study provides additional evidence suggesting that, when energy-based instruments are used, interruption of antithrombotic medication may not be necessary in mastectomy.
Limitations
This study has several limitations. First, due to the retrospective nature of the study, there may be missing information, and the accuracy of the data cannot be verified on all aspects, and a certain portion of bleeding complications may be missing from the data. However, it could be argued that this study therefore presents the minimum risk of bleeding complications. Almost all patients in this study underwent mastectomy with energy instruments, and therefore the data does not represent a typical group of mastectomy patients. Based on this study, the absolute risk of major bleeding complication following a single seroma aspiration cannot be directly estimated, since most aspirations were performed in primary healthcare, where records of all aspirations could not be retrieved. Consequently, bleeding risk could only be estimated per mastectomy and not per individual aspiration episode. To be able to evaluate the true risk of bleeding complication in seroma aspiration, a prospective follow-up study should be executed.
Conclusions
A significant proportion of post-mastectomy bleeding complications present later than 30 days after the surgery and are usually associated with preceding seroma aspiration. The risk is elevated especially in patients taking antithrombotic medications. The indication, technique, and setting of seroma aspiration in these high-risk patients should be carefully considered.
Acknowledgements
Not Applicable.
Role of the funding source
The funding source has had no role in the design, conducting, analysis, or reporting of the study.
Authors’ contributions
Conceptualization (AT), Methodology (AT, RA, MR), Data Curation (AT), Analysis and interpretation (AT, RA, MR), Writing the draft of the article (AT), critical revision of the article (RA, MR).
Funding
The study was supported by a grant from the Cancer Society of Southwest Finland.
Data availability
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
Declarations
Ethics approval and consent to participate
This research study was conducted retrospectively from data obtained for clinical purposes. The research protocol of the study was approved by the Hospital District of Southwest Finland (T537/2022). No ethical approval was required for this retrospective study.
Consent for publication
Not Applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A et al. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin. 2021;71(3):209–49. Available from: https://onlinelibrary.wiley.com/doi/full/10.3322/caac.21660 [DOI] [PubMed] [Google Scholar]
- 2.Omling E, Jarnheimer A, Rose J, Björk J, Meara JG, Hagander L. Population-based incidence rate of inpatient and outpatient surgical procedures in a high-income country. Br J Surg. 2017;105(1):86–95. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Williams BA, Honushefsky AM, Berger PB. Temporal Trends in the Incidence, Prevalence, and Survival of Patients With Atrial Fibrillation From 2004 to 2016. Am J Cardiol. 2017;120(11):1961–5. [DOI] [PubMed] [Google Scholar]
- 4.Douketis JD, Spyropoulos AC, Murad MH, Arcelus JI, Dager WE, Dunn AS et al. Perioperative Management of Antithrombotic Therapy: An American College of Chest Physicians Clinical Practice Guideline. Chest. 2022;162(5):e207–43. Available from: http://journal.chestnet.org/article/S0012369222013599/fulltext [DOI] [PubMed] [Google Scholar]
- 5.Chatterjee A, Pyfer B, Czerniecki B, Rosenkranz K, Tchou J, Fisher C. Early postoperative outcomes in lumpectomy versus simple mastectomy. J Surg Res. 2015;198(1):143–8. [DOI] [PubMed] [Google Scholar]
- 6.Hamelinck VC, Bastiaannet E, Pieterse AH, Merkus JWS, Jannink I, den Hoed IDM et al. A prospective comparison of younger and older patients’ preferences for breast-conserving surgery versus mastectomy in early breast cancer. J Geriatr Oncol. 2018;9(2):170–3. Available from: http://www.geriatriconcology.net/article/S1879406817301753/fulltext [DOI] [PubMed] [Google Scholar]
- 7.Konishi T, Fujiogi M, Shigemi D, Matsui H, Fushimi K, Tanabe M, et al. Risk Factors for Postoperative Bleeding Following Breast Cancer Surgery: A Nationwide Database Study of 477,108 Cases in Japan. World J Surg. 2022;46(12):3062–71. [DOI] [PubMed] [Google Scholar]
- 8.Tamminen A, Aaltonen RI, Ristola MT. Postoperative bleeding complications in breast conserving surgery and the role of antithrombotic medications: retrospective analysis of 4712 operations. World Journal of Surgical Oncology. 2024;22(1):1–7. Available from: https://wjso.biomedcentral.com/articles/10.1186/s12957-024-03511-5 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Tamminen A, Huttunen T, Meretoja T, Niinikoski L, Koskivuo I. Ultrasonic scissors decrease postoperative bleeding complications in mastectomy: A retrospective multicenter cohort study on 728 patients. Eur J Surg Oncol. 2023;49(1):68–75. [DOI] [PubMed] [Google Scholar]
- 10.Halme ALE, Roshanov PS, Tornberg SV, Lavikainen LI, Devereaux PJ, Tikkinen KAO. Timing of Major Postoperative Bleeding Among Patients Undergoing Surgery. JAMA Netw Open. 2024;7(4):e244581. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC10988355/ [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Ausen K, Hagen AI, Østbyhaug HS, Olafsson S, Kvalsund BJ, Spigset O et al. Topical moistening of mastectomy wounds with diluted tranexamic acid to reduce bleeding: randomized clinical trial. BJS Open. 2020;4(2):216–24. Available from: https://onlinelibrary.wiley.com/doi/full/10.1002/bjs5.50248 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Tamminen A. Life-Threatening Bleeding After Mastectomy and Deliverance by a Single Suture: A Case-Report. JPRAS Open. 2025; Available from: https://linkinghub.elsevier.com/retrieve/pii/S2352587825000671 [DOI] [PMC free article] [PubMed]
- 13.Kazzam ME, Ng P. Postoperative Seroma Management. [Updated 2023 Aug 14]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2025 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK585101/ [PubMed]
- 14.Schulman S, Anger SU, Bergqvist D, Eriksson B, Lassen MR, Fisher W. Definition of major bleeding in clinical investigations of antihemostatic medicinal products in surgical patients. J Thromb Haemost. 2010;8(1):202–4. [DOI] [PubMed] [Google Scholar]
- 15.Von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for Reporting Observational Studies. PLoS Med. 2007;4(10):e296. Available from: https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0040296 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Roulin D, Cerantola Y, Demartines N, Schäfer M. Systematic Review of Delayed Postoperative Hemorrhage after Pancreatic Resection. J Gastrointest Surg. 2011;15(6):1055–62. [DOI] [PubMed] [Google Scholar]
- 17.Devereaux PJ, Mrkobrada M, Sessler DI, Leslie K, Alonso-Coello P, Kurz A et al. Aspirin in Patients Undergoing Noncardiac Surgery. New England Journal of Medicine. 2014;370(16):1494–503. Available from: https://www.nejm.org/doi/full/10.1056/NEJMoa1401105 [DOI] [PubMed] [Google Scholar]
- 18.Pedersen RN, Bhaskaran K, Heide-Jørgensen U, Nørgaard M, Christiansen PM, Kroman N et al. Breast cancer recurrence after reoperation for surgical bleeding. Br J Surg. 2017;104(12):1665. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC5655703/ [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Chaudry IH, Ayala A. Mechanism of increased susceptibility to infection following hemorrhage. Am J Surg. 1993;165(2A Suppl):59S-67S. Available from: https://pubmed.ncbi.nlm.nih.gov/8439001/ [DOI] [PubMed] [Google Scholar]
- 20.Heo J, Youk TM, Seo KD. Anemia Is a Risk Factor for the Development of Ischemic Stroke and Post-Stroke Mortality. J Clin Med 2021. 2021;10(12):2556. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Kamel H, Johnston SC, Kirkham JC, Turner CG, Kizer JR, Devereux RB et al. Association Between Major Perioperative Hemorrhage and Stroke or Q-Wave Myocardial Infarction. Circulation. 2012;126(2):207. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC3986632/ [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Palomäki A, Kiviniemi T, Hartikainen JEK, Mustonen P, Ylitalo A, Nuotio I, et al. Postoperative Strokes and Intracranial Bleeds in Patients With Atrial Fibrillation: The FibStroke Study. Clin Cardiol. 2016;39(8):471–6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Spyropoulos AC, Douketis JD. How I treat anticoagulated patients undergoing an elective procedure or surgery. Blood. 2012;120(15):2954–62. Available from: 10.1182/blood-2012-06-415943 [DOI] [PubMed] [Google Scholar]
- 24.Chen A, Stecker E, Warden BA. Direct oral anticoagulant use: A practical guide to common clinical challenges. J Am Heart Assoc. 2020;9(13):17559. Available from: https://www.ahajournals.org/doi/10.1161/JAHA.120.017559 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Kazzam ME, Ng P. Postoperative Seroma Management. StatPearls. 2023; Available from: https://www.ncbi.nlm.nih.gov/books/NBK585101/ [PubMed]
- 26.Srivastava V, Basu S, Shukla VK. Seroma Formation after Breast Cancer Surgery: What We Have Learned in the Last Two Decades. J Breast Cancer. 2012;15(4):373–80. Available from: https://synapse.koreamed.org/articles/1036368 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Ebner F, Friedl TWP, de Gregorio A, Lato K, Bekes I, Janni W et al. Seroma in breast surgery: all the surgeons fault? Arch Gynecol Obstet. 2018;298(5):951–9. Available from: https://link.springer.com/article/10.1007/s00404-018-4880-8 [DOI] [PubMed] [Google Scholar]
- 28.Tamminen A, Aaltonen RI, Ristola MT. Ultrasonic instruments and concurrent antithrombotic medication in mastectomy: safe and effective. World Journal of Surgical Oncology 2025 23:1. 2025;23(1):1–9. Available from: https://wjso.biomedcentral.com/articles/10.1186/s12957-025-03712-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29.Gutierrez JJP, Rocuts KR. Perioperative Anticoagulation Management. StatPearls. 2023; Available from: https://www.ncbi.nlm.nih.gov/books/NBK557590/ [PubMed]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.