A systematic review and meta-analysis of oncological outcomes with transanal total mesorectal excision for rectal cancer.

AIM: Transanal total mesorectal (taTME) excision is a method used to assist in the radical removal of the rectum. By adopting the concept of natural orifice surgery, it offers potential benefits over conventional techniques. Early enthusiasm for this strategy led to its rapid and widespread adoption. The imposing of a local moratorium was precipitated by the discovery in Norway of an uncommon multifocal pattern of locoregional recurrence. The aim of this systematic review and meta-analysis was to determine the incidence of local recurrence after taTME for rectal cancer. METHOD: Conforming to the Cochrane Handbook for Systematic Reviews of Interventions and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines checklist, a systematic review and meta-analysis was conducted. This included case series and comparative studies between taTME and preferentially laparoscopic procedures published between 2010 and 2021. RESULTS: There were a total of 1175 studies retrieved. After removal and screening for quality and relevance, the final analysis contained 40 studies. The local recurrence rate following taTME was 3.4% (95% CI 2.9%-3.9%, I2 = 0%) in 4987 patients with follow-up durations ranging from 0.7 to 5.5 years. Compared with laparoscopic TME, local recurrence was not statistically different for the taTME group (p = 0.076); however, it was less probable (OR = 0.51, 95% CI 0.24-1.09, I2 = 0%). Systemic recurrence and circumferential resection margin status were secondary outcomes; however, the differences were not statistically significant. CONCLUSION: Our data suggest that the local recurrence for regular laparoscopic and transanal TME surgeries may be comparable, suggesting that taTME can be performed without influencing locoregional oncological outcomes in patients treated at specialized institutions and who have been cautiously selected.

Peri-operative, oncological and functional outcomes of robotic versus transanal total mesorectal excision in patients with rectal cancer: A systematic review and meta-analysis.

BACKGROUND: Comparative outcomes of robotic low anterior resection (rTME) and trans-anal total mesorectal excision (TaTME) in patients with low rectal cancer were evaluated. METHODS: A systematic online search was conducted using the following databases: PubMed, Scopus, Cochrane database, The Virtual Health Library, Clinical trials.gov and Science Direct. Comparative studies of rTME versus TaTME for low rectal cancer were included. Primary outcomes were postoperative complications, including anastomotic leak, surgical site infection, and Clavien-Dindo complication rate. Total operative time, conversion to open surgery, intra-operative blood loss, intensive therapy unit (ITU) and total hospital length of stay (LOS), oncological outcomes and functional outcomes were the other evaluated outcome parameters. RESULTS: A total of 12 studies with a total number of 3025 patients divided between rTME (n = 1881) and TaTME (n = 1144) groups were included. There was no significant difference between the two groups for total operative time (P = 0.39), conversion to open surgery (P = 0.29) and intra-operative blood loss (P = 0.62). Clavien-Dindo ≥ 3 complication rate (P = 0.47), anastomotic leak (P = 0.89), rates of re-operation (P = 0.62) and re-admission (P = 0.92), R0 resections (P = 0.52), ITU LOS (P = 0.63) and total hospital LOS (P = 0.30) also showed similar results between the two groups. However, the rTME group had higher rates of total harvested lymph nodes (P = 0.04) and complete total mesorectal excision (TME) resections (P = 0.05). Albeit with a limited dataset, the Wexner and low anterior resection syndrome (LARS) scores showed better functional results in the rTME group compared with the TaTME group (P = 0.0009 and P = 0.00001, respectively). CONCLUSION: Compared with TaTME, rTME seems to provide better functional outcomes, higher lymph node yield and more complete TME resections with a similar post-operative complications profile.

Modified pull-through coloanal anastomosis to avoid permanent stomas and reduce postoperative complications for lower rectal tumors.

BACKGROUND: We performed pull-through hand-sewn coloanal anastomosis immediately after sphincter-preserving ultralow anterior resection (ULAR) [pull-through ultra (PTU)] to avoid permanent stoma and reduce postoperative complications of lower rectal tumors. This study aimed to compare the clinical outcomes of PTU versus non-PTU (stapled or hand-sewn coloanal anastomosis with diverting stoma) after sphincter-preserving ULAR for lower rectal tumors. METHODS: This retrospective cohort study analyzed prospectively maintained data from 100 consecutive patients who underwent PTU (n = 29) or non-PTU (n = 71) after sphincter-preserving ULAR for rectal tumors between January 2011 and March 2023. In PTU, hand-sewn coloanal anastomosis was immediately performed using 16 stitches of 4-0 monofilament suture during primary surgery. The clinical outcomes were assessed. The primary outcomes were rates of permanent stomas and overall postoperative complications. RESULTS: The PTU group was significantly less likely to require a permanent stoma than the non-PTU group (P < 0.01). None of the patients in the PTU group required permanent stoma and the rate of overall complications was significantly lower in the PTU group (P = 0.01). The median operative time was comparable between the two groups (P = 0.33) but the median operative time during the second stage was significantly shorter in the PTU group (P < 0.01). The rates of anastomotic leakage and complications of Clavien-Dindo grade III were comparable between the two groups. Diverting ileostomy was performed in two patients with an anastomotic leak in the PTU group. The PTU group was significantly less likely to require a diverting ileostomy than those in the non-PTU group (P < 0.01). The composite length of hospital stay was significantly shorter in the PTU group (P < 0.01). CONCLUSIONS: PTU via immediate coloanal anastomosis for lower rectal tumors is a safe alternative to the current sphincter-preserving ULAR with diverting ileostomy for patients who wish to avoid a stoma.

Two-team lateral lymph node dissection assisted by the transanal approach for locally advanced lower rectal cancer: comparison with the conventional transabdominal approach.

BACKGROUND: An optimal surgical approach to lateral lymph node dissection (LLND) remains controversial. With the recent popularity of transanal total mesorectal excision, a two-team procedure combining the transabdominal and transanal approaches was established as a novel approach to LLND. This study aimed to clarify the safety and feasibility of two-team LLND (2team-LLND) and compare its short-term outcomes with those of conventional transabdominal LLND (Conv-LLND). METHODS: Between April 2013 and March 2020, 463 patients diagnosed with primary locally advanced rectal cancer underwent a transanal total mesorectal excision; among them, 93 patients who underwent bilateral prophylactic LLND were included in this single-center, retrospective study. Among these patients, 50 and 43 patients underwent Conv-LLND (the Conv-LLND group) and 2team-LLND (the 2team-LLND group), respectively. The short-term outcomes, including the operation time, blood loss volume, number of complications, and number of harvested lymph nodes, were compared between the two groups. RESULTS: The intraoperative and postoperative complications in the 2team-LLND group were equivalent to those in the Conv-LLND group; furthermore, the incidence of postoperative urinary retention in the 2team-LLND group was acceptably low (9%). Compared with the Conv-LLND group, the 2team-LLND group had a significantly shorter operation time (P = 0.003), lower median blood loss (P = 0.02), and higher number of harvested lateral lymph nodes (P = 0.0005). CONCLUSION: The intraoperative and postoperative complications of 2team-LLND were comparable with those of Conv-LLND. Thus, 2team-LLND was safe and feasible for advanced lower rectal cancer. Moreover, it was superior to Conv-LLND in terms of the operation time, blood loss volume, and number of harvested lateral lymph nodes. Therefore, it can be a promising LLND approach.

Feasibility and safety of robotic surgery for low rectal cancer combined with transanal total mesorectal excision.

PURPOSE: Laparoscopic surgery for low rectal cancer is often challenging. Transanal total mesorectal excision (TaTME) and robotic surgery have been introduced to overcome the technical difficulties in laparoscopic surgery and achieve more favorable outcomes. Hybrid robotic surgery, which combines TaTME with the abdominal robotic approach, incorporates the advantages of each of these surgical techniques and might achieve less invasive and safer surgery. This study evaluated the safety and feasibility of hybrid robotic surgery with TaTME (hybrid TaTME). METHODS: We retrospectively reviewed 162 TaTME cases performed at our department from September 2016 to May 2022. Among them, 92 cases of conventional TaTME and 30 of hybrid TaTME were eligible. We used propensity score matching analysis (PSM) to adjust for patients' characteristics and compared the short-term outcomes of the two treatment groups. RESULTS: Twenty-seven cases in each group were extracted using PSM. The operation time in hybrid TaTME was comparable to that in conventional TaTME. There was no significant difference in the postoperative hospital stay between the two groups. Other intra- and post-operative outcomes were also comparable between the two groups. Furthermore, no significant differences were observed between the two groups in the curative resection and recurrence rates. CONCLUSION: Hybrid TaTME for low rectal cancer was as favorable as conventional TaTME in producing satisfactory short-term outcomes. However, furthermore, larger-scale studies conducted over longer study periods are needed to evaluate the validity of the findings.

Impact of trans-anal versus laparoscopic total mesorectal excision on the surgical and pathologic outcomes of patients with rectal cancer: meta-analysis of randomized controlled trials.

BACKGROUND: Despite its profound impact on the oncologic outcomes of rectal cancer, the most optimal surgical approach to total mesorectal excision (TME) has not been identified yet. All previous meta-analyses on this subject have been based on observational studies. This meta-analysis was conducted to assess the surgical and oncologic outcomes of laparoscopic TME (LaTME) compared to trans-anal TME (TaTME), utilizing only randomized controlled trials. DESIGN: Systematic review and meta-analysis of randomized controlled trials. METHODS: We searched electronic databases (MEDLINE, Cochrane CENTRAL, Clinicaltials.gov) from 2010 onwards, for all published clinical trials comparing TaTME to LaTME. Results are presented as risk ratios, with 95% CI, and pooled using the random effects model. RESULTS: A total of 1691 patients, from 6 eligible randomized controlled trials, were included for analysis. Analyzed data showed no significant difference in morbidity (RR: 0.85, p = 0.15), mortality (RR: 0.50, p = 0.44), conversion to open (RR: 0.40, p = 0.07), or anastomotic leakage (RR: 0.73, p = 0.10) between TaTME and LaTME. There was also no difference in the rate of positive distal resection margin (DRM) (RR: 0.55, p = 0.10) or positive circumferential resection margin (CRM) (RR: 0.67, p = 0.30). Patients undergoing TaTME were more likely to have a complete TME (RR: 1.06, p = 0.002) and shorter hospital stays (RR: - 0.97, p < 0.00001). CONCLUSIONS: Patients undergoing TaTME for rectal cancer were more likely to have a complete TME when compared to LaTME, though this did not translate into improved distal or circumferential resection margin. Additionally, TaTME and LaTME had similar surgical outcomes except for shorter length of stay with TaTME.

Reducing anastomotic leakage in TaTME by mucosal coverage of staple lines: a pilot study with preliminary results.

PURPOSE: We have performed a single stapled anastomosis with double purse-string sutures as a Trans anal Total Mesorectal Excision (TaTME) reconstruction for low rectal cancer. We report an attempt to control local infection and reduce anastomotic leakage (AL) at this anastomotic site. PATIENTS AND METHODS: Fifty-one patients who underwent TaTME for low rectal cancer from April 2021 to October 2022 were included. TaTME was performed by two teams, and reconstruction was performed by anastomosis with a single stapling technique (SST). After the anastomosis was thoroughly cleaned, Z sutures were placed parallel to the staple line to suture the mucosa on the oral and anal side of the staple line and to cover the staple line circumferentially. Data on operative time, Distal Margin (DM), recurrence and postoperative complications including AL were prospectively collected. RESULTS: The mean age of patients was 67 years. There were 36 males and 15 females. The overall mean operative time was 283.1 min, and the mean Distal Margin was 2.2 cm. Postoperative complications were observed in 5.9% of the patients, but no AL was observed, nor any serious complications with Clavien-Dindo ≥ 3 grade. Of the 49 cases excluding Stage 4, postoperative recurrence was observed in 2 cases (4.9%). CONCLUSION: In patients with lower rectal cancer who underwent TaTME, additional mucosal coverage of the anastomotic staple line by transanal manipulation after reconstruction may be associated with a reduction in the incidence of postoperative AL. Further studies including late anastomotic complications are needed.

Transanal total mesorectal excision and delayed coloanal anastomosis without stoma for low rectal cancer.

The management of low rectal cancer is a perennial challenge for colorectal surgeons. The benefits of transanal total mesorectal excision (TaTME) in low rectal cancer are to secure the distal margin and avoid surgical space constraints within the deep pelvis. However, anastomotic leak remains an important concern. We report our technique and results combining TaTME with delayed coloanal anastomosis (DCAA) without bowel diversion. First, the splenic flexure, left colon and rectum are laparoscopically mobilized to mid-rectum. TaTME is performed to complete the distal rectal mobilization, and the specimen is delivered transanally and transected. The abdominoperineal colonic pull-through is secured to the anal canal and hypertonic dressing is applied regularly in the ward. The handsewn DCAA is performed one week later. An accompanying video demonstrates this technique. Five consecutive patients with low rectal cancer underwent TaTME with DCAA. All had upfront surgical resection except one who underwent total neoadjuvant therapy. Mean operative duration, blood loss, and length of hospital stay was 290 (250-375) min, 142 (10-200) ml and 11.6 (10-14) days respectively. One patient (20%) suffered a postoperative complication of persistent urinary retention, requiring an indwelling urinary catheter on discharge. There were no cases of open conversion and no instances of anastomotic leakage. Two patients (40%) had minor low anterior resection syndrome (LARS) and one (20%) had major LARS. TaTME and DCAA without stoma are complimentary techniques that augment the minimally invasive effects of laparoscopic sphincter-sparing low rectal cancer surgery, with good perioperative outcomes.

Functional outcomes after transanal total mesorectal excision (TaTME): a random forest analysis to predict patients' outcomes.

PURPOSE: Anorectal, sexual, and urinary dysfunction are common issues after rectal cancer surgery, although seldom explored. The primary aim of this study was to investigate postoperative anorectal functional results. METHODS: Patients with mid/low-rectal cancer treated with transanal TME (TaTME) with primary anastomosis with/without diverting stoma between 2015 and 2020 were reviewed and selected if they had a minimum follow-up of 6 months (from the primary procedure or stoma reversal). Patients were interviewed using validated questionnaires and the primary outcome was bowel function based on Low Anterior Resection Syndrome (LARS) scores. Statistical analyses were performed to identify clinical/operative variables correlated with worse outcomes. A random forest (RF) algorithm was computed to classify patients at a greater risk of minor/major LARS. RESULTS: Ninety-seven patients were selected out of 154 TaTME performed. Overall, 88.7% of the patients had a protective stoma and 25.8% reported major LARS at mean follow-up of 19.0 months. Statistical analyses documented that age, operative time, and interval to stoma reversal correlated with LARS outcomes. The RF analysis disclosed worse LARS symptoms in patients with longer operative time (> 295 min) and stoma reversal interval (> 5.6 months). If the interval ranged between 3 and 5.6 months, older patients (> 65 years) reported worse outcomes. Finally, no statistical difference was documented when comparing the rate of minor/major LARS in the first 27 cases versus others. CONCLUSION: One-quarter of the patients developed major LARS after TaTME. An algorithm based on clinical/operative variables, such as age, operative time, and time to stoma reversal, was developed to identify categories at risk for LARS symptoms.

Outcomes of open vs laparoscopic vs robotic vs transanal total mesorectal excision (TME) for rectal cancer: a network meta-analysis.

BACKGROUND: Total mesorectal excision (TME) for rectal cancer can be achieved using open (OpTME), laparoscopic (LapTME), robotic (RoTME), or transanal techniques (TaTME). However, the optimal approach for access remains controversial. The aim of this network meta-analysis was to assess operative and oncological outcomes of all four surgical techniques. METHODS: Ovid MEDLINE, EMBASE, and PubMed databases were searched systematically from inception to September 2020, for randomised controlled trials (RCTs) comparing any two TME surgical techniques. A network meta-analysis using a Bayesian random-effects framework and mixed treatment comparison was performed. Primary outcomes were the rate of clear circumferential resection margin (CRM), defined as > 1 mm from the closest tumour to the cut edge of the tissue, and completeness of mesorectal excision. Secondary outcomes included radial and distal resection margin distance, postoperative complications, locoregional recurrence, disease-free survival, and overall survival. Surface under cumulative ranking (SUCRA) was used to rank the relative effectiveness of each intervention for each outcome. The higher the SUCRA value, the higher the likelihood that the intervention is in the top rank or one of the top ranks. RESULTS: Thirty-two RCTs with a total of 6151 patients were included. Compared with OpTME, there was no difference in the rates of clear CRM: LapTME RR = 0.99 (95% (Credible interval) CrI 0.97-1.0); RoTME RR = 1.0 (95% CrI 0.96-1.1); TaTME RR = 1.0 (95% CrI 0.96-1.1). There was no difference in the rates of complete mesorectal excision: LapTME RR = 0.98 (95% CrI 0.98-1.1); RoTME RR = 1.1 (95% CrI 0.98-1.4); TaTME RR = 1.0 (95% CrI 0.91-1.2). RoTME was associated with improved distal resection margin distance compared to other techniques (SUCRA 99%). LapTME had a higher rate of conversion to open surgery when compared with RoTME: RoTME RR = 0.23 (95% CrI 0.034-0.70). Length of stay was shortest in RoTME compared to other surgical approaches: OpTME mean difference in days (MD) 3.3 (95% CrI 0.12-6.0); LapTME MD 1.7 (95% CrI - 1.1-4.4); TaTME MD 1.3 (95% CrI - 5.2-7.4). There were no differences in 5-year overall survival (LapTME HR 1.1, 95% CrI 0.74, 1.4; TaTME HR 1.7, 95% CrI 0.79, 3.4), disease-free survival rates (LapTME HR 1.1, 95% CrI 0.76, 1.4; TaTME HR 1.1, 95% CrI 0.52, 2.4), or anastomotic leakage (LapTME RR = 0.92 (95% CrI 0.63, 1.1); RoTME RR = 1.0 (95% CrI 0.48, 1.8); TaTME RR = 0.53 (95% CrI 0.19, 1.2). The overall quality of evidence as per Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessments across all outcomes including primary and secondary outcomes was deemed low. CONCLUSIONS: In selected patients eligible for a RCT, RoTME achieved improved distal resection margin distance and a shorter length of hospital stay. No other differences were observed in oncological or recovery parameters between (OpTME), laparoscopic (LapTME), robotic (RoTME), or trans-anal TME (TaTME). However, the overall quality of evidence across all outcomes was deemed low.

Transanal total mesorectal excision (TaTME) with delayed coloanal anastomosis versus TaTME with immediate coloanal anastomosis and temporary diversion in middle and low rectal cancer.

BACKGROUND: Transanal total mesorectal excision (TaTME) avoids the difficulty of laparoscopic dissection of the lower part of the rectum. The need for stoma is associated with many stoma-related complications. The objective was to compare TaTME with immediate coloanal anastomosis and protective ileostomy (TaTME-IA) versus Turnbull-Cutait delayed coloanal anastomosis (TaTME-TC). METHODS: A retrospective cohort study included patients with low rectal cancer at least 1 cm above the top of the anal sphincter. Patients had either TaTME-IA or TaTME-TC. Primary outcome measures were anastomotic and stoma-related complications. Secondary outcomes included rate of permanent stomas, local recurrence, continence, and quality of life (QOL). RESULTS: TaTME-IA was done in 25 patients versus 20 who had TaTME-TC. TaTME-IA had significantly longer mean operative time (p = 0.04) and shorter length of stay (LOS) (4.5 vs. 11.4 days; p = 0.0001) compared to TaTME-TC. Anastomotic leak was reported in two patients of TaTME-IA versus one patient of TaTME-TC (p = 0.77). Anastomotic stenosis was reported in one patient in each group. No significant difference between groups as regard continence, local recurrence, and QOL. CONCLUSION: TaTME-TC is a safe option that can be offered for patients with low rectal cancer who refuse or are not amenable to a temporary stoma. Anastomotic complications were similar in both groups. LOS was much longer in TaTME-TC, however, it avoids stoma complications. Both groups had similar functional oncologic outcomes and QOL.

Anal preservation on the psychology and quality of life of low rectal cancer.

INTRODUCTION: The aims of this study are to evaluate depression and quality of life (QOL) after laparoscopic abdominoperineal resection (LAPR) or transanal total mesorectal excision (TaTME) surgery in low rectal cancer (RC) patients. METHODS: This is a prospective observational cohort study. Patients were divided into two groups: either TaTME surgery or LAPR. Psychosocial distress and QOL were assessed using a questionnaire before surgery, at 6 months postsurgery, and 12 months postsurgery. The Hospital Anxiety and Depression Scale was used to assess symptoms of anxiety and depression. The European Organization for Research and Treatment of Cancer-QOL questionnaire core was used to estimate the QOL. RESULTS: In the TaTME group, the scores of psychosocial distress and QOL showed an obvious tendency to decrease and then recover. Meanwhile, in the LAPR group, these scores deteriorated significantly at 6 and 12 months, and the recovery was less pronounced. Multivariable analysis suggested that surgical options and tumor stage were significantly associated with psychosocial distress and QOL. CONCLUSION: For low RC, TaTME could significantly improve patients' QOL and reduce psychological distress as compared to patients with LAPR at 12 months after surgery.

Trans-anal surgery with the taTME technique for rectal gastrointestinal stromal tumors: a retrospective study.

PURPOSE: Rectal gastrointestinal stromal tumors (GISTs) surgery is often challenging owing to the anatomical constraints of the narrow pelvis and tumor hugeness. Despite the increasing number of patients undergoing trans-anal total mesorectal excision (taTME) globally, the feasibility of trans-anal surgery with the taTME technique for rectal GISTs remains unclear. We aimed to evaluate the feasibility of trans-anal surgery with the taTME technique for rectal GISTs. METHODS: Using a prospectively collected database, we retrospectively analyzed the clinical findings, surgical outcomes, pathological outcomes, urinary and anal functions, and prognoses of patients who underwent trans-anal surgery with the taTME technique for primary rectal GISTs at the National Cancer Center Hospital East from September 2014 to March 2020. RESULTS: Twenty-one patients with primary rectal GISTs were included in this study. The median distance from the anal verge to the lower edge of the tumor was 40 mm (range, 15-60 mm), and the median tumor size was 59 mm (range, 11-175 mm). Moreover, seven and 14 patients underwent one-team and two-team surgeries, respectively, with curative intent. Nineteen patients (90.5%) underwent anus-preserving surgery, and the urinary tracts were preserved in all cases. Two-team surgery showed a significantly lower blood loss volume and shorter operation time than one-team surgery (58 vs. 222 mL, P = 0.017; 184 vs 356 min, P = 0.041, respectively). The pathological negative-margin resection rate was 100%. During the follow-up period, no patient developed local GIST recurrence and one (4.8%) developed distant metastasis. CONCLUSION: Trans-anal surgery with the taTME technique is feasible for rectal GISTs, and two-team surgery may be more advantageous than one-team surgery in terms of operation time and blood loss.

Transanal total mesorectal excision for abdominoperineal resection is associated with poor oncological outcomes in rectal cancer patients: A word of caution from a multicentric Canadian cohort study.

AIM: The main objective of this study was to compare the oncological outcomes of patients undergoing abdominoperineal resection (APR) versus low anterior resection (LAR) through a transanal total mesorectal excision (taTME) approach. METHOD: A total of 360 adult patients with a diagnosis of rectal cancer were enrolled at participating centres from the Canadian taTME Expert Collaboration. Forty-three patients received taTME-APR and received 317 taTME-LAR. Demographic, operative, pathological and follow-up data were collected and merged into a single database. Results are presented as hazard ratio (HR) and 95% confidence interval. All analyses were performed in the R environment (v.3.6). RESULTS: The proportion of patients with a positive circumferential radial margin status was higher in the taTME-APR group than the taTME-LAR group (21% vs. 9%, p = 0.001). Complete TME was achieved in 91% of those undergoing APR compared with 96% of those undergoing LAR (p = 0.25). APR was associated with a greater rate of local recurrence relative to LAR, although it was not significant [crude HR = 3.53 (95% CI 0.92-13.53)]. Circumferential margin positivity was significantly associated with a higher rate of systemic recurrence [crude HR = 3.59 (95% CI 1.38-9.3)]. CONCLUSION: Our results demonstrate inferior outcomes in those undergoing taTME-APR compared with taTME-LAR. The use of this technique for this particular indication needs to be carefully considered.

Transanal total mesorectal excision outcomes for advanced rectal cancer in a complex surgical population.

BACKGROUND: Total mesorectal excision (TME) is the gold standard for oncologic resection in low and mid rectal cancers. However, abdominal approaches to TME can be hampered by poor visibility, inadequate retraction, and distal margin delineation. Transanal TME (taTME) is a promising hybrid technique that was developed to mitigate the difficulties of operating in the low pelvis and to optimize the circumferential resection and distal margins. METHODS: The objective of this study was to characterize our experience implementing taTME at our institution in a technically challenging patient population. We performed a retrospective review of consecutive patients who underwent taTMEs between November 2013 and May 2019 for rectal cancer at a tertiary community cancer center. Outcome measures included pathologic grading of TME specimen, post-operative complications, and oncologic outcomes. RESULTS: Forty-four patients with mid and low rectal cancer underwent low anterior resection via taTME. The most common staging modality was rectal MRI which demonstrated T3 or T4 tumors in 89% of our patients prior to neoadjuvant. Eighty-six percent of patients underwent neoadjuvant chemoradiation. The initial cases were performed sequentially as a single team, but we later transitioned to a synchronous, two-team approach. Ninety-one percent of TME grades were complete or near complete. Only one patient (2.3%) had a positive circumferential margin. Six patients developed anastomotic leaks with an overall anastomotic complication rate of 18.2%. Two patients (4.5%) with primary rectal cancer developed local recurrence, one of which developed multifocal local recurrence. CONCLUSIONS: Using the taTME approach on selected locally advanced low rectal cancers, especially in technically complex irradiated and obese male patients, has yielded comparably safe and effective outcomes to laparoscopic proctectomy.

S184: preoperative sarcopenia is associated with worse short-term outcomes following transanal total mesorectal excision (TaTME) for rectal cancer.

INTRODUCTION: Malnutrition and deconditioning impact postoperative morbidity and mortality. Computed tomography (CT) body composition variables are used as markers of nutritional status and sarcopenia. The objective of this study is to evaluate the impact of sarcopenia, using CT variables, on postoperative outcomes following transanal total mesorectal excision (TaTME) for rectal cancer. METHODS: This was an institutional retrospective cohort analysis of consecutive rectal cancer patients who underwent TaTME between April 2014 and May 2020. Psoas muscle index (PMI) was calculated from diagnostic CT scans. Based on previous studies, patients in the lowest PMI tertile by gender were considered sarcopenic. Fisher's exact and Mann-Whitney U test were used to compare categorical and continuous variables, respectively. Readmission rates and postoperative complications were compared between groups. Backward stepwise logistic regression was used to determine the association between sarcopenia and 30-day postoperative complications. RESULTS: 85 patients were analyzed, of which 63% were male, with a median age of 59 (IQR: 51-65), and median BMI of 28 (IQR: 24-32). Of the entire cohort, 34% (n = 29) were sarcopenic (median PMI 5.39 IQR: 4.49-6.71). No significant difference in baseline characteristics between sarcopenic and nonsarcopenic patients were observed. 55% of sarcopenic patients experienced a complication within 30 days compared to 24% of nonsarcopenic patients (p = 0.01). 41% of sarcopenic patients required hospital readmission within 30 days compared to 17% of their nonsarcopenic counterparts (p = 0.014). Sarcopenic patients also experienced significantly higher rates of post-operative small bowel obstruction (10% vs. 0%, p = 0.04). Multivariable analyses identified that sarcopenic patients have a fourfold increase in odds of experiencing a 30-day postoperative complication (OR: 4.44, 95%CI: 1.6-12.4, p < 0.05) after adjusting for gender. CONCLUSION: Preoperative sarcopenia is associated with increased 30-day postoperative complications following TaTME for rectal cancer. Postoperative complications can have serious oncologic implications by delaying adjuvant chemotherapy. Therefore, preoperative recognition of sarcopenia prior to undergoing TaTME for rectal cancer may provide an opportunity for early intervention with prehabilitation programs.

Deep learning-based automatic surgical step recognition in intraoperative videos for transanal total mesorectal excision.

BACKGROUND: Dividing a surgical procedure into a sequence of identifiable and meaningful steps facilitates intraoperative video data acquisition and storage. These efforts are especially valuable for technically challenging procedures that require intraoperative video analysis, such as transanal total mesorectal excision (TaTME); however, manual video indexing is time-consuming. Thus, in this study, we constructed an annotated video dataset for TaTME with surgical step information and evaluated the performance of a deep learning model in recognizing the surgical steps in TaTME. METHODS: This was a single-institutional retrospective feasibility study. All TaTME intraoperative videos were divided into frames. Each frame was manually annotated as one of the following major steps: (1) purse-string closure; (2) full thickness transection of the rectal wall; (3) down-to-up dissection; (4) dissection after rendezvous; and (5) purse-string suture for stapled anastomosis. Steps 3 and 4 were each further classified into four sub-steps, specifically, for dissection of the anterior, posterior, right, and left planes. A convolutional neural network-based deep learning model, Xception, was utilized for the surgical step classification task. RESULTS: Our dataset containing 50 TaTME videos was randomly divided into two subsets for training and testing with 40 and 10 videos, respectively. The overall accuracy obtained for all classification steps was 93.2%. By contrast, when sub-step classification was included in the performance analysis, a mean accuracy (± standard deviation) of 78% (± 5%), with a maximum accuracy of 85%, was obtained. CONCLUSIONS: To the best of our knowledge, this is the first study based on automatic surgical step classification for TaTME. Our deep learning model self-learned and recognized the classification steps in TaTME videos with high accuracy after training. Thus, our model can be applied to a system for intraoperative guidance or for postoperative video indexing and analysis in TaTME procedures.

UEG and EAES rapid guideline: Systematic review, meta-analysis, GRADE assessment and evidence-informed European recommendations on TaTME for rectal cancer.

BACKGROUND: Evidence and practice recommendations on the use of transanal total mesorectal excision (TaTME) for rectal cancer are conflicting. OBJECTIVE: We aimed to summarize best evidence and develop a rapid guideline using transparent, trustworthy, and standardized methodology. METHODS: We developed a rapid guideline in accordance with GRADE, G-I-N, and AGREE II standards. The steering group consisted of general surgeons, members of the EAES Research Committee/Guidelines Subcommittee with expertise and experience in guideline development, advanced medical statistics and evidence synthesis, biostatisticians, and a guideline methodologist. The guideline panel consisted of four general surgeons practicing colorectal surgery, a radiologist with expertise in rectal cancer, a radiation oncologist, a pathologist, and a patient representative. We conducted a systematic review and the results of evidence synthesis by means of meta-analyses were summarized in evidence tables. Recommendations were authored and published through an online authoring and publication platform (MAGICapp), with the guideline panel making use of an evidence-to-decision framework and a Delphi process to arrive at consensus. RESULTS: This rapid guideline provides a weak recommendation for the use of TaTME over laparoscopic or robotic TME for low rectal cancer when expertise is available. Furthermore, it details evidence gaps to be addressed by future research and discusses policy considerations. The guideline, with recommendations, evidence summaries, and decision aids in user-friendly formats can also be accessed in MAGICapp: https://app.magicapp.org/#/guideline/4494 . CONCLUSIONS: This rapid guideline provides evidence-informed trustworthy recommendations on the use of TaTME for rectal cancer.

Transanal total mesorectal excision: short- and long-term results of the first hundred cases of a certified colorectal cancer center in Germany.

BACKGROUND: Since 2010, laparoscopic transanal total mesorectal excision (TaTME) has been increasingly used for low and very low rectal cancer. It is supposed to improve visibility and access to the dissection planes in the pelvis. This study reports on short- and long-term outcomes of the first 100 consecutive patients treated with TaTME in a certified German colorectal cancer center. PATIENTS AND METHODS: Data were derived from digital patient files and official cancer registry reports for patients with TaTME tumor surgery between July 2014 and January 2020. The primary outcome was the 3-year local recurrence rate and local recurrence-free survival (LRFS). Secondary endpoints included overall survival (OAS), disease-free survival (DFS), operation time, completeness of local tumor resection, lymph node resection, and postoperative complications. The Kaplan-Meier method was employed for the survival analyses; competing risks were considered in the time-to-event analysis. RESULTS: During the observation period, the average annual operation time decreased from 272 to 178 min. Complete local tumor resection was achieved in 97% of the procedures. Major postoperative complications (Clavien-Dindo 3-4) occurred in 11% of the cases. At a median follow-up time of 2.7 years, three patients had suffered from a local recurrence. Considering competing risks, this corresponds to a 3-year cumulative incidence rate for local recurrence of 2.2% and a 3-year LRFS of 81.9%. 3-year OAS was 82.9%, and 3-year DFS was 75.7%. CONCLUSION: TaTME is associated with favorable short and long-term outcomes. Since it is technically demanding, structured training programs and more research on the topic are indispensable.

Transanal versus laparoscopic total mesorectal excision: a comparative study of long-term oncological outcomes.

BACKGROUND: Transanal total mesorectal excision (TaTME) is the most recent approach developed to improve pelvic dissection in surgery for mid and low rectal tumors. There are still inconsistencies regarding the technique's oncological results. The aim of this study was to analyze clinical and oncological outcomes of the learning curve of TaTME in comparison to laparoscopic TME (lapTME). METHODS: Rectal cancer patients who had TaTME and lapTME in two Portuguese colorectal units between March 2016 and December 2018 were eligible. Primary endpoints were 5-year overall survival, disease-free survival, and local recurrence. Secondary endpoints were clinical and pathological outcomes. RESULTS: Forty-four patients underwent TaTME (29 men) and 39 lapTME (27 men) with a median age of 69 and 66 (p = 0.093), respectively. No differences were observed concerning baseline characteristics, emphasizing their comparability. In the TaTME group, there were more hand-sewn anastomosis (0 lapTME versus 7 TaTME, p = 0.018) with significantly less distance to the dentate line (40 mm lapTME versus 20 mm TaTME, p = 0.005) and significantly more loop ileostomies performed (28 lapTME versus 41 TaTME, p = 0.001). There were no differences in post-operative mortality, morbidity, readmissions, and stoma closure. Groups were similar in relation to specimen quality, margins, and resectability; however, TaTME had a significantly higher node yield (14 lapTME versus 20 TaTME, p = 0.002). Finally, no disparities were noted in oncological outcomes, namely local and distant recurrence, 5-year overall survival, and disease-free survival. CONCLUSIONS: Even with the disadvantage of the learning curve of a new technique, TaTME appears to be comparable to lapTME, with similar long-term oncological outcomes. It has, however, a demanding learning curve, significant risk for morbidity and should be used only for selected patients.