Artificial intelligence-assisted decision making: Prediction of optimal level of distal mesorectal margin during transanal total mesorectal excision (taTME) using deep neural network modeling.

BACKGROUND: With steep posterior anorectal angulation, transanal total mesorectal excision (taTME) may have a risk of dissection in the wrong plane or starting higher up, resulting in leaving distal mesorectum behind. Although the distal mesorectal margin can be assessed by preoperative MRI, it needs skilled radiologist and high-definition image for accurate evaluation. This study developed a deep neural network (DNN) to predict the optimal level of distal mesorectal margin. METHODS: A total of 182 pelvic MRI images extracted from the cancer image archive (TCIA) database were included. A DNN was developed using gender, the degree of anterior and posterior anorectal angles as input variables while the difference between anterior and posterior mesorectal distances from anal verge was selected as a target. The predictability power was assessed by regression values (R) which is the correlation between the predicted outputs and actual targets. RESULTS: The anterior angle was an obtuse angle while the posterior angle varied from acute to obtuse with mean angle difference 35.5°±14.6. The mean difference between the anterior and posterior mesorectal end distances was 18.6±6.6mm. The developed DNN had a very close correlation with the target during training, validation, and testing (R=0.99, 0.81, and 0.89, P<0.001). The predicted level of distal mesorectal margin was closely correlated with the actual optimal level (R=0.91, P<0.001). CONCLUSIONS: Artificial intelligence can assist in either making or confirming the preoperative decisions. Furthermore, the developed model can alert the surgeons for this potential risk and the necessity of re-positioning the proctectomy incision.

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.

Local Recurrence of Rectal Cancer After Transanal Total Mesorectal Excision and Risk Factors: A Nationwide Multicenter Cohort Study in Japan.

Objective: To investigate the oncological outcomes after transanal total mesorectal excision (TaTME) for rectal cancer and risk factors for local recurrence (LR). Background: A high LR rate with a multifocal pattern early after TaTME has been reported in Norway and the Netherlands, causing controversy over the oncological safety of this technique. Methods: Twenty-six member institutions of the Japan Society of Laparoscopic Colorectal Surgery participated in this retrospective cohort study. A total of 706 patients with primary rectal cancer who underwent TaTME between January 2012 and December 2019 were included for analysis. The primary endpoint was the cumulative 3-year LR rate. Results: A total of 253 patients had clinical stage III disease (35.8%) and 91 (12.9%) had stage IV. Intersphincteric resection was performed in 318 patients (45.0%) and abdominoperineal resection in 193 (27.3%). There was 1 urethral injury (0.1%). A positive resection margin (R1) was seen in 42 patients (5.9%). Median follow-up was 3.42 years, and the 2- and 3-year cumulative LR rates were 4.95% (95% confidence interval: 3.50-6.75) and 6.82% (95% confidence interval: 5.08-8.89), respectively. A multifocal pattern was observed in 14 (25%) of 56 patients with LR. Tumor height from the anal verge, pathological T4 disease, pathological stage III/IV, positive perineural invasion, and R1 resection were significant risk factors for LR in multivariable analysis. Conclusions: In this selected cohort in which intersphincteric resection or abdominoperineal resection was performed in more than half of cases, oncological outcomes were acceptable during a median follow-up of more than 3 years.

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.

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.

Can the Single-stapling Technique Following Intersphincteric Resection with Transanal Total Mesorectal Excision Become the New Standard Anastomosis?

For transanal total mesorectal excision (TaTME), the indication for single-stapling technique (SST) has been expanded to include lower anastomosis, even in intersphincteric resection (ISR). We focused on the anastomotic techniques following ISR with TaTME and examined the feasibility and safety of the SST below the anorectal junction (ARJ). Data on postoperative anastomosis-related complications and anorectal function was evaluated in comparison to conventional manual hand-sewn coloanal anastomosis in ISR with TaTME. We examined patients with 3-6 cm tumors from the anal verge who underwent ISR with TaTME between January 2018 and March 2020, and whose anastomotic line was located below the ARJ. Postoperative short-term outcomes and anorectal functions were compared. We also analyzed the effects of various factors on major low anterior resection syndrome (LARS) using multivariate logistic regression analysis. In total, 87 patients-48 in the hand-sewn anastomosis group and 39 in the SST group-were included in this study. SST below the ARJ in ISR with TaTME did not exacerbate surgical outcomes, including anastomosis-related complications. The SST group had a significantly lower LARS score as compared to the hand-sewn anastomosis group, and the proportion of major LARS was significantly lower. Only hand-sewn anastomosis was identified as a statistically significant independent risk factor for major LARS. In TaTME, SST below the ARJ was safe and feasible and had a lower negative impact on postoperative anastomosis-related complications and anorectal function as compared to hand-sewn anastomosis. Thus, SST is a promising anastomotic option for patients with low-lying rectal tumors.

The role of transanal compared to laparoscopic total mesorectal excision (taTME vs. lapTME) for the treatment of mid-low rectal cancer in obese patients: outcomes of a multicenter propensity-matched analysis.

To compare the rate of sphincter-saving interventions between transanal and laparoscopic Total Mesorectal Excision in this particular group of patients. A multicentre observational study was conducted using a prospective database, including patients diagnosed with rectal cancer below the peritoneal reflection and BMI ≥ 30 kg/m2, who underwent minimally invasive elective surgery over a 5-year period. Exclusion criteria were (1) sphincter and/or puborectalis invasion; (2) multi-visceral resections; (3) palliative surgeries. The study population was divided into two groups according to the intervention: transanal or laparoscopic total mesorectal excision. The primary outcome was the rate of sphincter-saving surgery. Secondary outcomes included conversion, postoperative complications, quality of the specimen, and survival. A total of 93 patients were included; 40 (43%) transanal total mesorectal excision were compared to 53 (57%) laparoscopic. In addition, 35 cases of transanal approach were case-matched with an equal number of laparoscopic approaches, based on gender, tumor's height, and neoadjuvant therapy. In both groups, 43% of the patients had low rectal cancer; however, the rate of sphincter-saving surgery was significantly higher in the transanal group (97% vs. 71%, p = 0.003). There were no conversions to open surgery in the transanal group, compared to 2 cases in the laparoscopic group (6%) (p = 0.246). The percentage of major complications was similar, including the rate of anastomotic leakage (10% transanal vs. 19% laparoscopic, p = 0.835). In our experience, higher percentages of sphincter-saving procedures and lower conversion rates are potential benefits of using the transanal approach in a complex surgical setting population of obese patients with mid-low rectal tumors when compared to laparoscopic.

A longer pelvis is associated with longer operative time in transanal total mesorectal excision (TME) but not in laparoscopic TME. Results from a retrospective cohort study.

Introduction: A narrow pelvis, obesity, and bulky low rectal tumor are perceived as risk factors for intraoperative difficulties during total mesorectal excision (TME), particularly in the laparoscopic approach. A transanal approach has been developed to overcome the difficulties encountered during laparoscopic TME. There is no clear definition of a narrow pelvis that would guide preoperative surgical planning. Aim: To evaluate different MRI-based pelvic measurements in patients undergoing TME to identify factors predictive of intraoperative difficulties in transabdominal compared to the transanal approach. Material and methods: A retrospective analysis of 48 patients treated with laparoscopic TME and 62 with transanal TME for rectal tumors was performed. Multiple logistic regressions analyzed demographic, tumor, and pelvimetry factors that correlate with intraoperative difficulties measured as intraoperative blood loss, operation time, and perioperative complications in both surgical approaches. Results: Multivariate analysis showed that age was associated with higher blood loss (OR = 1.09, 95% CI: 1.00-1.18, p = 0.038), male gender (OR = 0.13, 95% CI: 0.02-0.86, p = 0.029) and body mass index with longer operating time (OR = 1.32, 95% CI: 1.06-1.64, p = 0.010) in the LAR group. Multivariate analysis showed that age increased the odds of intraoperative blood loss > 100 ml (OR = 1.08, 95% CI: 1.02-1.15, p = 0.013), and pelvic length > 119 mm increased operating time (OR = 5.76, 95% CI: 1.33-25.01, p = 0.016) in the TaTME group. Conclusions: Pelvic measurements are not associated with intraoperative difficulties in LAR. Longer pelvis was associated with longer operative time in TaTME.

Transanal Total Mesorectal Excision for Rectal Cancer.

Transanal total mesorectal excision (taTME) is a technique where rectal dissection is begun transanally in a "bottom-up" fashion. This technique facilitates dissection of the most distal part of the rectum and allows the establishment of the distal margin for rectal cancer. TaTME has proven its utility in facilitating low rectal dissection with significantly lower conversion rates and acceptable perioperative, oncological, and functional outcomes. However, taTME remains a challenging technique to learn and adopt. This article describes the technique, indications, and outcomes of taTME in rectal cancer during the last decade.

Predictors of Clostridium difficile infection after stoma reversal following TaTME surgery.

BACKGROUND:  The aim of this study was to determine the incidence of Clostridium Difficile infection (CDI) after stoma reversal in patients who underwent transanal Total Mesorectal Excision (TaTME) and to evaluate variables correlated with this post-operative infection. METHODS:  Patients who underwent stoma reversal surgery following TaTME for rectal cancer between 2015 and 2023 at a high-volume Institution, were retrospectively reviewed for the post-operative occurrence of diarrhea and in-hospital CDI (positive toxin in the stools). Patients were divided into the following subgroups according to the post-operative course: Group A-no clinical symptoms; Group B-mild diarrhea (< 10 evacuations/day); Group C-severe watery diarrhea (> 10 evacuations/day) with CDI negative; and Group D-severe watery diarrhea (> 10 evacuations/day) CDI positive. Clinical and laboratory data were analyzed for their correlation with CDI. A machine learning approach was used to determine predictors of diarrhea following stoma reversal. RESULTS:  A total of 126 patients were selected, of whom 79 were assessed as Group A, 16 Group B, 25 Group C and 6 (4.8%) Group D. Univariable analysis documented that delayed stoma reversal correlated with CDI (Group A mean interval 44.6 weeks vs. Group D 68.4 weeks, p 0.01). The machine learning analysis confirmed the delay in stoma closure as a probability factor of presenting diarrhea; also, diarrhea probability was 80.5% in males, 77.8% in patients who underwent neoadjuvant therapy, and 63.9% in patients who underwent adjuvant therapy. CONCLUSIONS:  Stoma reversal surgery can result in moderate rate of in-hospital CDI. Time-to stoma reversal is a crucial variable significantly related with this adverse outcome.

What Is the Comparative Efficacy of Surgical, Endoscopic, Transanal Resection, and Radiotherapy Modalities in the Treatment of Rectal Cancer?

BACKGROUND: Rectal cancer is a significant healthcare burden, and effective treatment is crucial. This research aims to compare the effectiveness of surgical and endoscopic resection, transanal resection, and radiotherapy. METHODS: A literature analysis was conducted in order to identify relevant studies, by comparing the different surgical approaches and variables affecting treatment decisions. The findings were analyzed and synthesized to provide a comprehensive overview. RESULTS: Surgical treatment, particularly TME (total mesorectal excision), proved consistent efficacy in achieving complete tumor resection and improving long-term survival. Endoscopic treatment and transanal resection techniques were promising for early-stage tumors but were associated with higher local recurrence rates. Radiotherapy, especially in combination with chemotherapy, played a crucial role in locally advanced cases, improving local control and reducing recurrence risk. Patient data, tumor characteristics, and healthcare system factors were identified as important factors in treatment modality selection. CONCLUSION: Surgical treatment, specifically TME, remains the recommended standard approach for rectal cancer, providing excellent oncological outcomes. Endoscopic treatment and transanal resection techniques can be considered for selected early-stage cases, while radiotherapy is beneficial for locally advanced tumors. Treatment decisions should be personalized based on patient and tumor characteristics, considering the available resources and expertise within the healthcare system.

Transanal Total Mesorectal Excision Considering the Embryology Along the Fascia in Rectal Cancer Patients.

BACKGROUND/AIM: Transanal total mesorectal excision (TaTME) remains a challenging technique for rectal dissection. This study aimed to evaluate the clinical and oncological outcomes of TaTME, compared to those of the laparoscopic TME (LaTME) in rectal cancer. PATIENTS AND METHODS: Using propensity score-matched analyses, we analyzed retrospective data from 134 consecutive patients with rectal cancer who underwent TaTME or LaTME from January 2011 to June 2020 in our hospital. Clinical and oncological outcomes were evaluated. The primary endpoint was the 2-year local recurrence rate. RESULTS: Before data analysis, significant group-dependent differences were observed only in the tumor height (p<0.01). After analysis, preoperative patient demographics were similar between the TaTME and LaTME groups. The operative time was significantly shorter in the TaTME group (p=0.02), and the rates of hand-sewn anastomosis and protective loop ileostomy were significantly higher (p<0.01). The TaTME group showed a null conversion to open surgery compared to the LaTME group (5.9%). The postoperative complications, including anastomotic leak, were comparable between the two groups. However, the rate of Clavien-Dindo grade III tended to be lower in the TaTME group (p=0.07). There were no statistically significant differences in terms of pathological findings, and the 2-year local recurrence rate was similar between the two groups (both 5.9%). CONCLUSION: TaTME based on embryology along the fascia is feasible and seems a safe alternative to LaTME in selected patients with rectal cancer when considering the conversion rate and the operative time.

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.

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.

Long-term outcomes after transanal total mesorectal excision for rectal cancer in Denmark: A prospective multicenter study from the late implementation phase.

PURPOSE: The aim of this study was to evaluate the long-term surgical and oncological outcomes after transanal total mesorectal excision (TaTME) for rectal cancer during an implementation phase on a national level. METHOD: This is a retrospective review of prospectively recorded data. Registration was initiated by the Danish Colorectal Cancer Group in order to assess the quality of care during the implementation of TaTME in Denmark. Data from four centers were pooled for simultaneous analysis. Short-term data was available from a prior study, and long-term data regarding recurrences, chemotherapy, and mortality was collected. RESULTS: From August 2016 to April 2019, 115 TaTME procedures were registered. Patients were predominantly male (n = 85, 74%) with mid-rectal (n = 88, 77%) tumors. The overall local recurrence rate was 7.8% (n = 9) of which six patients also had systemic recurrence. Mean long-term follow-up was 59.4 months, and median time to local recurrence was 24.9 months. Local recurrences occurred predominantly among initial implementation cases. The overall mortality rate was 13% (n = 15). Of the 17 patients with recurrence, 35% (n = 6) died and developed either solely distant recurrence (n = 2, 12%) or in combination with local recurrence (n = 4, 24%). CONCLUSION: We found acceptable long-term oncological results after TaTME during the implementation phase in Denmark. There was an accumulation of local recurrences in the early phase of the study which emphasizes the importance of thorough training and proctoring when starting the approach.

Transanal Total Mesorectal Excision for Extended Surgery in the Early Stage After Introduction.

BACKGROUND/AIM: The effectiveness of transanal total mesorectal excision (Ta-TME) in extended surgery (ES) has been discussed. This study examined the short-term outcomes of the first 31 patients who underwent Ta-TME after its introduction and verified the safety of Ta-TME in ES in the early stage following its introduction. PATIENTS AND METHODS: Thirty-one consecutive patients who underwent Ta-TME between December 2021 and January 2023 at our institution were included. The indications for Ta-TME were rectal tumors that could be palpated during rectal examination and bulky tumors that were deemed unresectable without Ta-TME. Short-term outcomes were retrospectively compared between patients who underwent normal Ta-TME, (n=27, TME group) and patients who underwent ES beyond TME (n=4, ES group). The data are shown as the median and interquartile range. Statistical analysis was performed with the Mann-Whitney U-test and Fisher's exact test. RESULTS: Total pelvic exenteration (TPE) was performed in the 4th and 8th patients; the 9th patient underwent a combined resection of the right adnexa and urinary bladder wall. The 31st patient underwent a combined resection of the uterus and the right adnexa. The operative time was 353 [285-471] vs. 569 [411-746] min for the TME and ES groups (p=0.039). Blood loss was 8 [5-40] vs. 45 [23-248] ml (p=0.065); postoperative hospital stay was 15 [10-19] vs. 11 [9-15] days (p=0.201); postoperative complications (higher than grade III) were 5 (19%) vs. 0 (p=1.000). Negative CRM was achieved in all cases. CONCLUSION: Ta-TME in ES was as safe as normal Ta-TME in the early stage after its introduction.

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.

Case report on a rare complication after transanal total mesorectal excision (TaTME) for rectal malignancy vesicorectal fistula.

INTRODUCTION AND IMPORTANCE: Transanal Total Mesorectal Excision (TaTME) represents the latest surgical approach in rectal cancer management. We present a rare case of vesicorectal fistula (VRF) following a complication of TaTME surgery. CASE PRESENTATION: A 67-year-old male underwent a Hartmann's procedure for perforated rectosigmoid cancer in 2019. He was lost to follow-up and re-presented in 2021 with synchronous cancer of the transverse colon and rectum. A two-team surgical approach was utilized: open subtotal colectomy (transabdominal approach) with concurrent excision of rectal stump (TaTME approach). Intraoperatively, an inadvertent bladder injury was identified and repaired. 8 months later, he re-presented with the passage of urine per rectum. Imaging and endoscopy revealed a VRF with cancer recurrence at the rectal stump. CLINICAL DISCUSSION: VRF is an uncommon complication of TaTME that carries a significant physical and psychological impact on the patient. While shown to be a safe and useful technique, the long-term oncological outcomes of TaTME are still awaited. Unique complications have been reported with TaTME, including gas embolism and injuries to the genitourinary structures, in which the latter caused the eventual VRF formation in our patient. CONCLUSION: Revisional surgery for recurrent disease is challenging and can result in rare complications, especially in patients with distorted anatomy and when new surgical techniques are utilized. Radiotherapy further causes unpredictable tissue healing quality. The challenge remains for proper patient selection with individualization of surgical approaches, while keeping a close eye on the oncological outcomes of the patient.

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.