Abstract
Introduction:
Total mesorectal excision (TME) with delayed coloanal anastomosis (DCAA) is surgical option for low rectal cancer, replacing conventional immediate coloanal anastomosis (ICAA) with bowel diversion. This study aimed to assess the outcomes of transanal TME (TaTME) with DCAA versus laparoscopic TME (LTME) with ICAA versus robotic TME (RTME) with ICAA.
Methods:
This was a retrospective propensity score-matched analysis of patients who underwent elective TaTME-DCAA between November 2021 and June 2022. Patients were propensity-score matched in a ratio of 1:3 to patients who underwent LTME-ICAA and RTME-ICAA from January 2019 to December 2020. Outcome measures were histopathologic results, postoperative morbidity, function, and inpatient costs.
Results:
Twelve patients in the TaTME-DCAA group were compared with 36 patients in the LTME-ICAA and RTME-ICAA groups each after propensity score matching. Histopathologic results and postoperative morbidity rates were statistically similar. Overall stoma-related complication rates in the ICAA groups were 11%. Median total length of hospital stays for TME plus stoma reversal surgery was similar across all techniques (10 vs. 10 vs. 9 days; P=0.532). Despite a significantly shorter duration of follow-up, bowel function after TaTME-DCAA was comparable to that of LTME-ICAA and RTME-ICAA. Overall median inpatient costs of TaTME-DCAA were comparable to LTME-ICAA and significantly cheaper than RTME-ICAA ($31,087 vs. $29,927 vs. $36,750; P=0.002).
Conclusions:
TaTME with DCAA is a feasible and safe technique compared with other minimally invasive methods of TME, while avoiding bowel diversion and stoma-related complications, as well as comparing favorably in terms of overall hospitalization costs.
Key Words: total mesorectal excision, TaTME, delayed coloanal anastomosis, low rectal cancer, robotic surgery, laparoscopic surgery
In 1981, Bill Heald demonstrated the oncological importance of total mesorectal excision (TME) in the surgical management of rectal cancer through dissection between the mesorectal fascia and presacral fascia.1 For decades, TME had become the gold standard for mid to low rectal cancer surgery, on the basis of improved local control. The quality of the TME plane has been shown to be associated with improved disease-free survival, reduced local and distant recurrences, as well as increased overall survival, on univariate analyses.2
Compared with open surgery, laparoscopic colorectal surgery has the advantages of reduced postoperative pain, faster recovery, decreased morbidity and quicker discharge. The laparoscopic modality has become an integral part of colorectal enhanced recovery after surgery programmes.3–5 Meta-analyses of randomised controlled trials show comparable long-term oncological outcomes between open and laparoscopic TME (LTME) methods for rectal cancer.6–9
In recent years, 2 other minimally invasive techniques for TME have emerged: robotic total mesorectal excision (RTME) and transanal total mesorectal excision (TaTME). The robotic approach offers improved operator ergonomics and increased dexterity of the operating instruments. This is useful where a narrow pelvis hinders dissection with conventional laparoscopic instruments.10 The transanal “bottom-up” technique overcomes several limitations of “top-down” methods of TME, such as the restricted working space and the challenge of securing the distal resection margin.10
Although some differences in short-term results including histopathologic resection quality and postoperative complications have been demonstrated, 2 recent network meta-analyses comparing the various minimally invasive techniques of TME showed similar long-term oncological outcomes.11,12 Data concerning postoperative function and procedural cost differences are relatively lacking. Given the established long-term safety of all TME techniques and improved cancer survivorship in general, patient outcomes beyond oncology have been gaining importance.
Another facet to the surgical management of low rectal cancer is the need for bowel diversion. A defunctioning stoma is frequently created after low or ultralow anterior resection to prevent the catastrophic consequences of anastomotic leakage.13 However, bowel diversion has been associated with a considerable risk of morbidity and stoma-related problems.14
Delayed coloanal anastomosis (DCAA) with a Turnbull-Cutait abdominoperineal pull-through has been shown to be a viable alternative to immediate coloanal anastomosis (ICAA) after ultralow anterior resection for low rectal cancer.15–17 The pull-through allows formation of perianastomotic adhesions before subsequent coloanal anastomosis, minimizing the risk of intraperitoneal leakage and removing the need for defunctioning stoma creation.
Although DCAA can be performed with any minimally invasive method of TME, in our experience, TaTME may be most synergistic with the DCAA technique.18 This is the first study comparing TaTME-DCAA with LTME-ICAA and RTME-ICAA, comparing short-term postoperative outcomes, bowel function, and overall costs of hospitalization.
METHODS
From November 2021 to June 2022, all patients who underwent elective TaTME with DCAA for non-metastatic low rectal cancer at the Department of Colorectal Surgery, Singapore General Hospital were included in the study. The propensity score-matched cohorts were identified from a prospectively maintained database of patients who underwent elective LTME or RTME with ICAA from January 2019 to December 2020. The matching weight method19 was used to match the 3 treatment groups in the ratio of 1:3 based on age, sex, body mass index, American Society of Anaesthesiologists (ASA) score, and use of neoadjuvant radiotherapy. Statistical analyses were performed using R statistical software (version 4.1.2; R Foundation for Statistical Computing), and SPSS® version 23 (IBM, Armonk). Continuous data were expressed as mean (SD) when normally distributed (determined by Shapiro-Wilk test) or as median [interquartile range (IQR)] when non-normally distributed. A one-way ANOVA or Kruskal-Wallis H test was used to analyze continuous variables. Categorical variables expressed in frequency (%) and analyzed using the Fisher Exact test. A P value < 0.050 was considered to be statistically significant.
Only patients who underwent ultralow anterior resection for low rectal adenocarcinoma with complete removal of the mesorectum and anal sphincter preservation were included in the study. All patients underwent preoperative computed tomography (CT) and magnetic resonance imaging (MRI) for distant and local staging respectively. Low rectal cancer was defined as those with a distal edge <6 cm from the anal verge, based on preoperative MRI.
Patients who underwent emergency surgery, multivisceral resection, or pelvic exenteration, were excluded from the study. Patients with distant metastases, or those who underwent defunctioning stoma creation before anterior resection where also excluded. In addition, patients who had not undergone reversal of stoma at the time of propensity score-matching were excluded.
Operative resection was performed only after neoadjuvant chemoradiotherapy for the appropriate patients as recommended by multidisciplinary team meeting. For these patients, CT and MRI staging were repeated after chemoradiotherapy. Preoperative chemoradiation was not mandatory for clinical T3 or N1 tumors which were both circumferential resection margin negative and extramural venous invasion negative.
All procedures were performed by experienced colorectal surgeons with more than 150 prior minimally invasive rectal cancer resections per individual. 2L of polyethylene glycol was used as preoperative bowel preparation for all patients. Operative technique for TaTME with DCAA was previously described,18 with a single surgical team sequential approach starting with laparoscopic colorectal mobilization and transanal completion of TME using the transanal minimally invasive surgery (TAMIS) platform. Figure 1 demonstrates several main steps of the TaTME DCAA procedure.
FIGURE 1.
(A) Transanal total mesorectal excision is performed using the transanal minimally invasive surgery platform, (B) transanal specimen delivery and proximal bowel transection after completed bowel mobilization, (C) abdominoperineal pull-through segment (postoperative day 5 appearance), (D) amputation of the pull-through segment and handsewn delayed coloanal anastomosis.
The colonic pull-through segment invariably causes fecal incontinence, resulting in patient discomfort and nursing care difficulties if diet is allowed. Therefore, all patients who underwent TaTME with abdominoperineal pull-through at our unit were kept on per oral clear feeds only and commenced total parental nutrition (TPN) on postoperative day 1 or 2 in the ward through central catheter up till DCAA creation.18 Peripheral parental nutrition was not practised at our unit at the time of writing. Regular per oral diet was allowed immediately after the DCAA surgery.
All RTME procedures were performed using the da Vinci Si surgical system. The newer da Vinci Xi system was not available at our unit before 2022. All ultralow anterior resections with ICAA for low rectal cancer at our unit were defunctioned as per routine practice. Oral feeding was commenced as clinically indicated for the LTME-ICAA and RTME-ICAA cohorts with ostomy nurse education in the ward on postoperative day 1 or 2.
Postoperative anorectal function was assessed using 2 validated scoring systems. The Low Anterior Resection Syndrome (LARS) score,20 comprises 5 questions with the cumulative score stratifying patients into having no LARS, minor LARS, or major LARS. The Wexner score ranges from 0 to 20 and assesses fecal incontinence, with 0 reflecting perfect continence and 20 reflecting total incontinence.21 Questionnaires were administered on outpatient follow-up. Scores reflected in this study were taken from the latest outpatient visit.
The cost of inpatient stay was the overall cost of hospitalization, inclusive of surgical costs, room charges, and ward treatment fees, etc. These cost figures were calculated before government subsidies or insurance coverage and do not reflect final out-of-pocket payment. Outpatient expenditures e.g., for specialist outpatient clinic or stoma nurse clinic fees, were not included. Costs of patient readmission were not included. Unless otherwise stated, all cost figures in this manuscript are reported in Singapore dollar (1 Singapore dollar=0.74 United States dollar at time of writing).
Ethics approval for the study was granted by the SingHealth centralized institutional review board (CIRB reference number 2022/2024).
RESULTS
Over the 8-month duration, 12 consecutive patients underwent TaTME with DCAA for low rectal cancer. Propensity score-matching identified 36 patients who underwent LTME with ICAA and 36 patients who underwent RTME with ICAA at our unit from 2019 to 2020. Comparison of patient and tumor characteristics are shown in Table 1.
TABLE 1.
Patient and Tumor Characteristics of Patients who Underwent TaTME-DCAA Versus a Propensity Score-matched Cohort of LTME-ICAA and RTME-ICAA for Low Rectal Cancer
| Characteristic | TaTME-DCAA n=12 | LTME-ICAA n=36 | RTME-ICAA n=36 | P |
|---|---|---|---|---|
| Age (y), mean (SD) | 69.3 ± 6.2 | 67.9 ± 11.2 | 66.4 ± 8.5 | 0.777 |
| Sex | 0.865 | |||
| Male | 8 (66.7) | 23 (63.9) | 21 (58.3) | |
| Female | 4 (33.3) | 13 (36.1) | 15 (41.7) | |
| ASA score | 0.971 | |||
| 1 | 0 | 1 (2.8) | 2 (5.6) | |
| 2 | 9 (75.0) | 27 (75.0) | 25 (69.4) | |
| 3 | 3 (25.0) | 8 (22.2) | 9 (25.0) | |
| BMI (kg/m2), median (IQR) | 23.0 (21.2, 26.0) | 23.6 (21.6, 25.9) | 22.3 (20.6, 24.2) | 0.657 |
| Hypertension | 8 (66.7) | 19 (52.8) | 14 (38.9) | 0.218 |
| Diabetes mellitus | 4 (33.3) | 9 (25.0) | 7 (19.4) | 0.605 |
| Ischemic heart disease | 1 (8.3) | 4 (11.1) | 1 (2.8) | 0.362 |
| Previous stroke | 0 | 1 (2.8) | 0 | 1.000 |
| Smoking history | 0.561 | |||
| No | 7 (58.3) | 23 (63.9) | 22 (61.1) | |
| Yes | 1 (8.3) | 6 (16.7) | 9 (25.0) | |
| Ex-smoker | 4 (33.3) | 7 (19.4) | 5 (13.9) | |
| Preop chemoradiation | 2 (16.7) | 10 (27.8) | 8 (22.2) | 0.829 |
| Preop MRI DFAV (cm), median (IQR) | 5.1 (4.8, 5.8) | 5.0 (4.1, 5.4) | 5.0 (4.0, 5.7) | 0.612 |
| Preop serum CEA (ng/mL), median (IQR) | 2.5 (1.8, 3.9) | 3.00 (2.0, 8.2) | 4.00 (2.9, 6.8) | 0.367 |
| Preop serum albumin (g/L), median (IQR) | 41.0 (38.0, 42.0) | 40.0 (38.0, 42.0) | 39.0 (37.0, 42.0) | 0.250 |
Values in parentheses represent frequency unless otherwise stated.
ASA indicates American Society of Anaesthesiologists; BMI, body mass index; CEA, carcinoembryonic antigen; DCAA, delayed coloanal anastomosis; ICAA, immediate coloanal anastomosis; IQR, interquartile range; LTME, laparoscopic total mesorectal excision; MRI DFAV, magnetic resonance imaging distance from anal verge; Preop, preoperative; RTME, robotic total mesorectal excision; TaTME, transanal total mesorectal excision.
Histopathologic outcomes are shown in Table 2. RTME had the longest distal resection margin, followed by LTME and TaTME, but this difference was not statistically significant. Although RTME had a higher proportion of positive resection margins and intermediate grade TME quality, these differences were also not significant. There were no instances of positive proximal margins or poor specimen TME quality in the study population. Tumor size, lymph node harvest, as well as pathologic T and N stages were comparable across the 3 cohorts.
TABLE 2.
Histopathologic Characteristics of Resected Specimens After TaTME-DCAA Versus LTME-ICAA Versus RTME-ICAA for Low Rectal Cancer
| Characteristic | TaTME-DCAA n=12 | LTME-ICAA n=36 | RTME-ICAA n=36 | P |
|---|---|---|---|---|
| Tumor largest diameter (cm), median (IQR) | 3.7 (3.3, 5.1) | 3.5 (2.8, 5.0) | 4.3 (3.0, 6.0) | 0.418 |
| Resection margins (cm), median (IQR) | ||||
| Proximal margin | 8.3 (7.3, 11.0) | 10.5 (8.2, 15.0) | 8.3 (6.0, 11.5) | 0.073 |
| Distal margin | 1.0 (0.8, 1.5) | 1.4 (1.0, 2.8) | 1.5 (1.1, 3.0) | 0.625 |
| Closest radial margin | 1.0 (0.7, 1.2) | 1.0 (0.5, 2.1) | 1.2 (0.5, 2.0) | 0.781 |
| Margin involvement | 0.794 | |||
| Margins clear | 12 (100.0) | 35 (97.2) | 33 (91.7) | |
| CRM involved | 0 | 1 (2.8) | 2 (5.6) | |
| Distal margin involved | 0 | 0 | 1 (2.8) | |
| TME quality* | 0.355 | |||
| Good | 12 (100.0) | 35 (97.2) | 32 (88.9) | |
| Intermediate | 0 | 1 (2.8) | 4 (11.1) | |
| Poor | 0 | 0 | 0 | |
| Total lymph node harvest | 20.0 (20.0, 25.5) | 20.0 (15.0, 16.0) | 21.0 (14.0, 24.5) | 0.730 |
| Pathologic T stage† | 0.498 | |||
| pCR | 1 (8.3) | 2 (5.6) | 2 (5.6) | |
| T1 | 2 (16.7) | 3 (8.3) | 2 (5.6) | |
| T2 | 0 | 9 (25.0) | 10 (27.8) | |
| T3 | 9 (75.0) | 20 (55.6) | 21 (58.3) | |
| T4 | 0 (0.0) | 2 (5.6) | 1 (2.8) | |
| Pathologic N stage† | 0.294 | |||
| N0 | 5 (41.7) | 25 (69.4) | 20 (55.6) | |
| N1 | 7 (58.3) | 9 (25.0) | 13 (36.1) | |
| N2 | 0 (0.0) | 2 (5.6) | 3 (8.3) | |
Values in parentheses represent frequency unless otherwise stated.
Based on TME grading by Quirke et al.22
Based on American Joint Committee on Cancer 8th Edition.
CRM indicates circumferential resection margin; DCAA, delayed coloanal anastomosis; ICAA, immediate coloanal anastomosis; IQR, interquartile range; LTME, laparoscopic total mesorectal excision; pCR, pathologic complete response; RTME, robotic total mesorectal excision; TaTME, transanal total mesorectal excision.
Perioperative outcomes are provided in Table 3. Although not statistically significant, TaTME-DCAA was the quickest procedure of the 3, at a median of 22 minutes faster than LTME-ICAA and 52 minutes quicker than RTME-ICAA. All patients in the LTME and RTME groups underwent stapled coloanal anastomosis. All DCAA were performed handsewn, at a median of 7 days after TaTME. All anastomoses were performed as a straight anastomosis without colonic J-pouch.
TABLE 3.
Perioperative Outcomes of Patients who Underwent TaTME-DCAA Versus LTME-ICAA Versus RTME-ICAA for Low Rectal Cancer
| Characteristic | TaTME-DCAA n=12 | LTME-ICAA n=36 | RTME-ICAA n=36 | P |
|---|---|---|---|---|
| Index operation duration (min), median (IQR) | 308 (260, 333) | 330 (240, 400) | 360 (245, 465) | 0.567 |
| Index LOS (d), median (IQR) | 10.0 (8.5, 12.0) | 6.0 (4.0, 9.0) | 5.0 (4.0, 6.0) | <0.001 |
| Time to DCAA post-TaTME (d), median (IQR) | 7.0 (7.0, 8.0) | — | — | — |
| Time to stoma reversal (mo), median (IQR) | — | 5.0 (3.0, 8.0) | 7.0 (5.0, 11.0) | 0.091 |
| Stoma reversal LOS (d), median (IQR) | — | 4.0 (3.0, 5.0) | 4.0 (3.0, 5.0) | 0.884 |
| Overall LOS (d) median (IQR) | 10.0 (8.5, 12.0) | 10.0 (7.0, 14.0) | 9.0 (7.0, 11.0) | 0.532 |
| 30-d postop complications | ||||
| Yes | 3 (25.0) | 12 (33.3) | 8 (22.2) | 0.600 |
| Clavien-Dindo grade 1 or 2 | 2 (16.7) | 9 (25.0) | 7 (19.4) | 0.820 |
| Clavien-Dindo grade 3 or 4 | 1 (8.3) | 3 (8.3) | 1 (2.8) | 0.554 |
| Stoma-related complications | - | 4 (11.1) | 4 (11.1) | 0.645 |
| Readmissions | 1 (8.3) | 2 (5.6) | 3 (8.3) | 0.556 |
| LARS score | 0.905 | |||
| 0-20, no LARS | 7 (58.3) | 19 (52.8) | 23 (63.9) | |
| 21-29, minor LARS | 2 (16.7) | 9 (25.0) | 7 (19.4) | |
| 30-42, major LARS | 3 (25.0) | 6 (22.2) | 6 (16.7) | |
| Wexner score, median (IQR) | 9.0 (5.0, 13.0) | 9.0 (4.5, 15.0) | 7.0 (4.0, 11.5) | 0.252 |
| Follow-up duration (mo), median (IQR) | 7.0 (5.5, 12.0) | 28.0 (21.0, 35.0) | 28.0 (25.0, 36.0) | < 0.001 |
Values in parentheses represent frequency unless otherwise stated.
DCAA indicates delayed coloanal anastomosis; ICAA, immediate coloanal anastomosis; IQR, interquartile range; LARS, low anterior resection syndrome; LOS, length of stay; LTME, laparoscopic total mesorectal excision; Postop, postoperative; RTME, robotic total mesorectal excision; TaTME, transanal total mesorectal excision.
RTME-ICAA had the shortest median index hospital length of stay at 5 days, 1 day quicker than LTME-ICAA and one half that of TaTME-DCAA (P < 0.001). There were no operative conversions. All stoma reversals were performed open, after confirmation of anastomotic integrity with a contrast study. The median time to stoma reversal was 5 and 7 months for the LTME-ICAA group and RTME-ICAA group, respectively, with a 4-day median postoperative hospital stay after stoma closure in either group. The total length of hospital stays for TME surgery plus stoma reversal surgery was statistically similar across all techniques, although RTME-ICAA was a median of 1 day quicker than the other 2 groups.
The overall 30-day postoperative morbidity rates were comparable, including the rates of lower-grade complications (Clavien-Dindo 1 or 2) and higher-grade complication (Clavien-Dindo 3 or 4). The breakdown and descriptions of each complication are detailed in Table 4. The overall rates of stoma-related adverse events were 11% in both the LTME-ICAA and RTME-ICAA cohorts, with all but one complication occurring late post-discharge (after 30 days). One patient suffered high output stoma with dehydration in the postoperative inpatient period after RTME. No patients in the TaTME-DCAA group underwent salvage stoma creation as a result of postoperative morbidity. The descriptions of all stoma-related complications are given in Table 4.
TABLE 4.
Breakdown of Perioperative Complications After TaTME-DCAA Versus LTME-ICAA Versus RTME-ICAA for Low Rectal Cancer
| TaTME-DCAA n=12 | LTME-ICAA n=36 | RTME-ICAA n=36 | |
|---|---|---|---|
| 30-d Clavien-Dindo grade 1 and 2 complications | Urine retention requiring post-discharge IDC (n=2) | Postop ileus requiring nasogastric suction and delayed feeding (n=8) Urine retention requiring post-discharge IDC (n=1) |
Urine retention requiring post-discharge IDC (n=3) Superficial wound infection (n=1) Rhabdomyolysis (n=1) New onset atrial fibrillation (n=1) Dehydration from high stoma output (n=1) |
| 30-d Clavien-Dindo grade 3 and 4 complications | Bleeding anastomotic ulcer requiring endoscopic hemostasis (n=1) | Anastomotic leak (n=1) Ureteric injury requiring double-J stent insertion (n=1) Bladder injury requiring repair (n=1) |
Prolonged postop ileus with myocardial infarction (n=1) |
| Stoma-related complications | — | High output stoma (n=2) Stomal prolapse (n=2) Parastomal herniation (n=1) |
High output stoma (n=1) Stomal prolapse (n=1) Parastomal herniation (n=1) Stoma site outflow obstruction (n=1) |
DCAA indicates delayed coloanal anastomosis; ICAA, immediate coloanal anastomosis; IDC, indwelling urinary catheter; LTME, laparoscopic total mesorectal excision; RTME, robotic total mesorectal excision; TaTME, transanal total mesorectal excision.
Follow-up duration was significantly longer in the LTME-ICAA and RTME-ICAA cohorts compared with the TaTME-DCAA cohorts as adoption of the latter procedure had not begun in our unit until end 2021. Despite this, the proportions of patients with no LARS, minor LARS, and major LARS were similar. Median postoperative Wexner scores were also statistically comparable across the groups, although the RTME-ICAA group had the lowest postoperative Wexner score on follow-up.
Hospitalization cost comparisons are shown in Table 5, with the breakdown of median cost components given in Fig. 2. Relevant contributory elements to the various components of costs are as follows:
Surgical procedure: surgical procedure fees, operative facility fee
Consumables: surgical staplers, energy devices, other single-use devices, TAMIS platform for TaTME, robotic platform for RTME
Ward treatment and room charges: room/bed charges, ward doctor reviews, ward nursing care, allied health intervention (physiotherapist, dietitian, etc)
Ward procedures and investigations: blood tests, imaging, peripheral or central line insertions
Drug charges: medications, intravenous fluids, TPN
TABLE 5.
Comparison of Hospitalization Costs for Patients who Underwent TaTME-DCAA Versus LTME-ICAA Versus RTME-ICAA for Low Rectal Cancer
| Cost | TaTME-DCAA n=12 | LTME-ICAA n=36 | RTME-ICAA n=36 | P |
|---|---|---|---|---|
| Cost of index hospitalization (SGD), median (IQR) | 31,087 (28,874, 33,057) | 22,170 (20,388, 23,651) | 29,508 (27,647, 29,907) | 0.001 |
| Cost of hospitalization for stoma reversal (SGD), median (IQR) | — | 7907 (7067, 8716) | 7530 (7152, 8054) | 0.589 |
| Total cost of inpatient stay (SGD), median (IQR) | 31,087 (28,874, 33,057) | 29,927 (27,868, 31,611) | 36,750 (35,129, 37,677) | 0.002 |
DCAA indicates delayed coloanal anastomosis; ICAA, immediate coloanal anastomosis; IQR, interquartile range; LTME, laparoscopic total mesorectal excision; RTME, robotic total mesorectal excision; SGD, Singapore dollar; TaTME, transanal total mesorectal excision.
FIGURE 2.
Breakdown of median cost components of total inpatient stay for patients who underwent TaTME-DCAA versus LTME-ICAA versus RTME-ICAA for low rectal cancer. DCAA indicates delayed coloanal anastomosis; ICAA, immediate coloanal anastomosis; LTME, laparoscopic total mesorectal excision; RTME, robotic total mesorectal excision; TaTME, transanal total mesorectal excision.
Inpatient costs of the of the index hospitalization for TaTME-DCAA was the highest among the 3 groups, at a median of $1579 more than RTME-ICAA and $8917 more than LTME-ICAA (P=0.001). Increased costs were contributed by having 2 surgical procedures within the same admission, greater length of stay, higher cumulative room charges, and costs for TPN administration. TPN was given through a peripherally inserted central catheter. Additional blood investigations for the monitoring of electrolytes, renal and hepatic functions were also required, as well as regular review by the nutrition team. The average duration of TPN use in the TaTME-DCAA cohort was 5 days.
With the addition of hospitalization charges for stoma reversal, RTME-ICAA became the costliest approach overall, at a median $6823 more than LTME-ICAA and $5663 more than TaTME-DCAA (P=0.002). This substantial disparity was largely driven by the higher surgical procedure and consumable costs with RTME. TaTME-DCAA was still more costly overall compared with LTME-ICAA, but the median difference was only $1160.
DISCUSSION
The management of low rectal cancer deep within the confines of the bony pelvis is a perennial challenge for colorectal surgeons. Minimally invasive robotic and transanal platforms for TME build on the established benefits of laparoscopic surgery, reducing operative abdominal trauma and enabling more precise tissue dissection, while also offering unique solutions to overcome the technical difficulties of deep pelvic surgery.10
Despite theoretical advantages of each approach, no single method has demonstrated conclusive superiority over the others thus far, with similar long-term oncological results.11,12 The international, multicentre ROLARR trial showed no benefit with robotic-assisted TME over laparoscopic TME.23 Another international, multicentre trial, COLOR III, is ongoing and hypothesizes oncological superiority of TaTME over LTME.24
Regardless of technique, anastomotic breakdown remains an important concern after TME, with distal anastomoses having a significantly higher risk of leak.25 Borstlap et al26 demonstrated a 20% risk of leak in a large cohort of patients after low anterior resection, with a 10% incidence of chronic sinus formation. In a study of 525 patients who underwent low anterior resection with coloanal anastomosis, the absence of fecal diversion was associated with a more than 2-fold risk of sepsis, more than 6-fold incidence of septic shock, and >6-fold need for reoperation compared with having a defunctioning stoma.27 Meta-analysis of randomised controlled trials affirms that bowel diversion reduces the anastomotic leak and reoperation rates after rectal cancer surgery.13
However, the price of protection is high. The risk of stoma-related morbidity has been well documented,14,28,29 including high stoma output leading to electrolyte disturbances and dehydration, local stoma skin or outlet issues, and the negative stoma-associated psychosocial impact.30 A previous temporary ostomy has been shown to worsen body image issues and embarrassment long after reversal of the stoma, compared with having no stoma at all.31 Moreover, stoma closure is associated with a 17% incidence of morbidity as well as a risk of mortality.32
The randomised trial by Biondo et al15 demonstrated the safety and feasibility of DCAA compared with ICAA for low rectal cancer, with delayed anastomosis resulting in a lower leak rate while avoiding a stoma. Laparoscopy was the first choice TME approach in this study. In “top-down” methods of TME, distal bowel transection using a linear stapler closes off the distal conduit which needs to be re-opened for abdominoperineal pull-through. If the distal transection is performed through sharp dissection instead, the lack of proximal luminal control increases the risk of bowel content spillage and pelvic contamination in patients with suboptimal bowel preparation.
In our experience, TaTME is the most technically synergistic with DCAA compared with other methods of TME.18 Using the TAMIS endoscopic platform, the mucosa distal to the tumor is first closed using a purse-string suture before a circumferential rectotomy is performed. Closure of the proximal bowel prevents contamination whereas the open rectotomy stump after completed TME allows for transanal natural orifice specimen extraction of the specimen and facilitates delivery of the abdominoperineal pull-through segment.18 For these reasons, DCAA was and is currently only performed together with TaTME at our unit. A TaTME-ICAA arm was not included for analysis as too few such procedures had been performed to allow meaningful statistical comparison.
Before the study, postoperative bowel function was a pertinent concern after the TaTME-DCAA approach, as TaTME and DCAA both involve stretching of the anal sphincter. The TaTME and DCAA techniques have individually not been demonstrated to produce worse long-term bowel function compared with other “top-down” TME methods24,33,34 and ICAA,15,16 respectively. To our knowledge, only one prior study reported functional outcomes after combined TaTME with DCAA.35 Despite a significantly shorter follow-up duration, TaTME-DCAA did not result in inferior bowel function compared with LTME-ICAA and RTME-ICAA.
In our cohort, all DCAA were handsewn, whereas all ICAA were done stapled. The comparable functional scores for DCAA versus ICAA contrasted with a previous study by Ramage et al,36 which demonstrated worse bowel function with handsewn coloanal anastomosis. There were also no instances of anastomotic stricture in the study cohort.
Moreover, overall functional results of all 3 groups, evaluated using the LARS and Wexner scores, compared favorably to that of existing studies.37,38 This may be partially attributable to early pharmacological therapy and referral to an onsite gastrointestinal functional unit for evaluation and biofeedback therapy for suitable patients.39 It is noteworthy that the presence of a defunctioning ileostomy itself as well as prolonged time to ostomy closure were both found to be significant risk factors for major LARS on recent meta-analysis.40
The economic impact of DCAA was another area of interest. A recent cost-effectiveness comparison of DCAA versus ICAA after laparoscopic TME estimated a 9% overall reduction in cost with DCAA,41 largely contributed by a decrease in anastomotic or stoma-related complications and readmissions. This study used publicly available United Kingdom National Health Service (NHS) reference costs and model probabilities for perioperative outcomes based on existing studies.41 A criticism of this study is that inpatient costs, postoperative length of hospital stays, and complication rates vary considerably across institutions and geographical locations. Therefore, fidelity of using NHS cost data based on probabilities elsewhere may be limited.
Our study demonstrates that overall inpatient costs of TaTME-DCAA are comparable to LTME-ICAA and significantly cheaper than RTME-ICAA. Furthermore, these figures do not reflect costs of stoma-related complications, outpatient visits to the ostomy nurse practitioner, and ongoing costs for stoma appliances and products, which are expected to be considerable. A recent meta-analysis by Vogel et al14 showed 6% pooled readmission rate for ileostomy-induced dehydration, with average added costs of USD 2750 to 5924 per patient. The stoma-related complication rate among both ICAA groups in our study was 11%; however, “minor” complications including peristomal skin irritation and stoma bag leakage were not routinely documented. These issues contribute to the negative psychosocial effects of the stoma beyond the monetary impact.
Although the DCAA component is technically straightforward, TME is a difficult procedure with the risk of serious morbidity. TaTME, in particular, has been associated with increased postoperative morbidity and inferior oncological outcomes.42 This has been attributed to improper implementation of the technique and learning curve issues.43,44 A recent systematic review of 45 studies assessing the learning curves for minimally invasive TME estimated at least 50 procedures for LTME, 32 to 75 procedures for RTME, and 36 to 54 procedures for TaTME to surmount the learning curve.45 In our study, all TME procedures were performed by experienced surgeons who had achieved technical competency after supervised structured proctorship.
The main limitation of the study is the relatively small number of patients in the TaTME-DCAA arm with a short follow-up period. However, preliminary review of perioperative outcomes and bowel function data in this cohort was deemed suitable for formal analysis in view of consistently good results and the novel nature of the comparison. Propensity-score matching for patients in the LTME-ICAA and RTME-ICAA arms in the ratio of 1:3 was undertaken to reduce sampling bias.
Our results demonstrate that TaTME with DCAA may be a feasible and safe technique, with similar short-term outcomes, histopathologic results, morbidity rates and bowel function compared with other minimally invasive methods of TME, while avoiding bowel diversion and stoma-related complications. Overall inpatient costs of TaTME-DCAA are comparable to LTME-ICAA and significantly cheaper than RTME-ICAA.
Footnotes
The authors declare no conflicts of interest.
Contributor Information
Isaac Seow-En, Email: isaac.seow.en@gmail.com.
Jingting Wu, Email: wujting@gmail.com.
Ivan En-Howe Tan, Email: roxynox@gmail.com.
Yun Zhao, Email: emilyzhaoyun@yahoo.com.
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