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.

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.

Changes to circulating tumor cells in the central vein during laparoscopic versus transanal endoscopic surgeries for rectal cancer: can surgical approach make a difference?

Background: The oncological safety of transanal total mesorectal excision (taTME) remains uncertain, and its special surgical approach may contribute to tumor cell dissemination. Thus, we conducted a study to investigate the impact of surgical approach on circulating tumor cell (CTC) counts and phenotypes in rectal cancer. Methods: This is a prospective randomized controlled study (ClinicalTrials: NCT05109130). The patients were randomized to either the taTME (n = 49) or laparoscopic TME (laTME) (n = 48) groups. Blood samples were collected from the central vein to measure CTC counts and phenotypes at three time points: preoperative (t1), immediately post-tumor removal (t2), and one week post-surgery (t3). The effect of surgical procedure on CTCs at each time point was analyzed, with the primary endpoint being the change in CTC counts from t1 to t3 for each surgical approach. This study adheres to Consolidated Standards of Reporting Trials Guidelines. Results: The baseline clinicopathologic characteristics of the laTME and taTME groups were balanced. The change in CTC count from t1 to t3 was 1.81 ± 5.66 in the laTME group and 2.18 ± 5.53 in the taTME group. The taTME surgery was non-inferior to laTME in terms of changing CTC counts (mean difference [MD]: -0.371; 95% confidence interval [CI]: -2.626 to 1.883, upper-sided 95% CI of 1.883 < 2, non-inferiority boundary value). Compared with that at t1, the CTC count at t2 did not change significantly. However, higher CTC counts were detected at t3 than at t2 in the taTME (P = 0.032) and laTME (P = 0.003) groups. From t1 to t3, CTC counts significantly increased in both the taTME (P = 0.008) and laTME (P = 0.031) groups. There were no significant differences in CTC phenotype changes between the two groups from t1 to t3. Conclusions: Compared with laTME, taTME did not affect CTC counts and phenotypes. Our findings indicate that taTME is not inferior to laTME in terms of CTC changes from an oncological perspective.

Oncologic outcomes following transanal total mesorectal excision: the United States experience.

AIM: The benefits and short-term outcomes of transanal total mesorectal excision (taTME) for rectal cancer have been demonstrated previously, but questions remain regarding the oncologic outcomes following this challenging procedure. The purpose of this study was to analyze the oncologic outcomes following taTME at high-volume centers in the USA. METHODS: This was a multicenter, retrospective observational study of 8 tertiary care centers. All consecutive taTME cases for primary rectal cancer performed between 2011 and 2020 were included. Clinical, histopathologic, and oncologic data were analyzed. Primary endpoints were rate of local recurrence, distal recurrence, 3-year disease recurrence, and 3-year overall survival. Secondary endpoints included perioperative complications and TME specimen quality. RESULTS: A total of 391 patients were included in the study. The median age was 57 years (IQR: 49, 66), 68% of patients were male, and the median BMI was 27.4 (IQR: 24.1, 31.0). TME specimen was complete or near complete in 94.5% of cases and the rates of positive circumferential radial margin and distal resection margin were 2.0% and 0.3%, respectively. Median follow-up time was 30.7 months as calculated using reverse-KM estimator (CI 28.1-33.8) and there were 9 cases (2.5%) of local recurrence not accounting for competing risk. The 3-year estimated rate of disease recurrence was 19% (CI 15-25%) and the 3-year estimated overall survival was 90% (CI 87-94%). CONCLUSION: This large multicenter study confirms the oncologic safety and perioperative benefits of taTME for rectal cancer when performed by experienced surgeons at experienced referral centers.

Long-term restoration of bowel continuity after rectal cancer resection and the influence of surgical technique: A nationwide cross-sectional study.

AIM: Literature on nationwide long-term permanent stoma rates after rectal cancer resection in the minimally invasive era is scarce. The aim of this population-based study was to provide more insight into the permanent stoma rate with interhospital variability (IHV) depending on surgical technique, with pelvic sepsis, unplanned reinterventions and readmissions as secondary outcomes. METHOD: Patients who underwent open or minimally invasive resection of rectal cancer (lower border below the sigmoid take-off) in 67 Dutch centres in 2016 were included in this cross-sectional cohort study. RESULTS: Among 2530 patients, 1470 underwent a restorative resection (58%), 356 a Hartmann's procedure (14%, IHV 0%-42%) and 704 an abdominoperineal resection (28%, IHV 3%-60%). Median follow-up was 51 months. The overall permanent stoma rate at last follow-up was 50% (IHV 13%-79%) and the unintentional permanent stoma rate, permanent stoma after a restorative procedure or an unplanned Hartmann's procedure, was 11% (IHV 0%-29%). A total of 2165 patients (86%) underwent a minimally invasive resection: 1760 conventional (81%), 170 transanal (8%) and 235 robot-assisted (11%). An anastomosis was created in 59%, 80% and 66%, with corresponding unintentional permanent stoma rates of 12%, 24% and 14% (p = 0.001), respectively. When corrected for age, American Society of Anesthesiologists classification, cTNM, distance to the anorectal junction and neoadjuvant (chemo)radiotherapy, the minimally invasive technique was not associated with an unintended permanent stoma (p = 0.071) after a restorative procedure. CONCLUSION: A remarkable IHV in the permanent stoma rate after rectal cancer resection was found. No beneficial influence of transanal or robot-assisted laparoscopy on the unintentional permanent stoma rate was found, although this might be caused by the surgical learning curve. A reduction in IHV and improving preoperative counselling for decision-making for restorative procedures are required.

Analysis of Bacterial Culture of Fluid in the Surgical Area in Transanal Total Mesorectal Excision and Laparoscopic Total Mesorectal Excision.

Purpose: To investigate the clinical value of the bacterial culture of fluid in the surgical area in laparoscopic transanal total mesorectal excision (Lap-taTME) and laparoscopic total mesorectal excision (Lap-TME). Methods: Clinical data of 106 patients with rectal cancer who had undergone surgery were retrospectively collected, including 56 patients in the Lap-taTME group and 50 patients in the Lap-TME group. In the Lap-taTME group, the initial pelvic fluid, the rectal cavity fluid after purse-string suture, and the pelvic cavity fluid after anastomosis were collected and recorded as culture No. 1, No. 2, and No. 3, respectively. In the Lap-TME group, culture No. 1 and No. 3 were collected as done in the Lap-taTME group. The culture results and postoperative complications were statistically analyzed. Results: The positive rate of culture No. 1 was zero in both groups, and there were 6 cases (10.7%) with positive culture No. 2 in the Lap-taTME group. However, the number of patients with positive culture No. 3 (7, 12.5%) and cumulative positive culture cases (11, 19.6%) in the Lap-taTME group were significantly higher than those in the Lap-TME group (0) (all P < .05). Pelvic infection occurred in 4 (7.1%) of the 11 cases (19.6%) with positive culture in the Lap-taTME group, accounting for 36.4% (4/11). There were no significant intergroup differences in anastomotic leakage and pelvic infection (all P > .05). Conclusion: Positive bacterial culture of fluid during Lap-taTME indicates an increased risk of pelvic infection after operation. Lap-taTME is more prone to intraoperative contamination than Lap-TME but does not significantly increase the risk of postoperative pelvic infection.

Conversion rate to open surgery during transanal total mesorectal excision (TaTME) for rectal cancer: a single-center experience.

Minimally invasive techniques for rectal cancer have demonstrated considerable advantages in terms of faster recovery and less post-operative complications. However, due to the complex anatomy and a limited surgical field, conversion to open surgery is still sometimes required, with a negative impact on the short-and long-term outcomes. The purpose of this study was to analyse the conversion rate to open abdominal surgery during laparoscopic transanal total mesorectal excision (TaTME) procedures performed at a high-volume Italian referral center. All consecutive TaTME performed for mid-to-low rectal cancer between 2015 and 2023 were reviewed, independently if treated with a primary anastomosis (with/without a diverting ostomy) or an end stoma. All procedures were performed using a standardized approach by the same surgical team. Patients with benign diagnosis that underwent different-from rectal resection procedures and cases pre-operatively scheduled for open surgery were excluded. The primary outcome of interest was the rate of conversion, defined as an un-planned intraoperative switch to open surgery using a midline laparotomy. Secondary aims included the comparison of patients who had a longer vs shorter operative time. Out of 220 patients, 210 were selected. In 187 cases, a primary anastomosis was performed, while 23 patients received a terminal colostomy (1 in the converted group; 22 in the full MIS- TaTME group, 10.6%). A surgical approach modification occurred in two cases, with a conversion rate of 0.95%. Median operative time was 281 min. Reasons for conversions included intra-operative difficulties impairing the mini-invasive procedure without intra-operative complications in one case, and difficulties in the laparoscopic control of an intraoperative bleeding due to a splenic lesion in another patient. Male sex and a higher BMI were found to be statistically significantly associated to longer operative time (respectively: p = 0.001 and p = 0.0025). In a high-volume center, a standardized TaTME is associated to a low conversion rate to open abdominal surgery.

Comparison of the short-term surgical outcomes of lateral lymph node dissection for low rectal cancer using a robotic-assisted transabdominal approach alone or supported by a transanal approach.

BACKGROUND: Lateral lymph node metastases are a major cause of local recurrence after surgery for advanced low rectal cancer. Lateral lymph node dissection (LLND) may reduce the risk of local recurrence in patients with suspected lateral lymph node metastasis. Recent reports have shown that robotic-assisted LLND can help to reduce the postoperative complication rate, such as urinary disturbance. Furthermore, with the advent of transanal total mesorectal excision, a novel LLND procedure that combines a transabdominal approach with a transanal approach has been reported. This study aimed to clarify the safety and feasibility of robotic-assisted LLND supported by a transanal approach for advanced low rectal cancer. METHODS: Thirty-nine patients diagnosed to have low rectal cancer between June 2019 and May 2023 were retrospectively enrolled and divided according to whether they underwent LLND via a robotic-assisted transabdominal approach alone (transabdominal group, n = 19) or in combination with a transanal approach (2team group, n = 20). The patient characteristics and short-term surgical outcomes were compared between the two groups. RESULTS: The total operation time was significantly shorter in the 2team group than in the transabdominal group (366 min vs. 513 min, P < 0.001), as was the time taken to perform unilateral LLND (64 min vs. 114 min, P < 0.001). Furthermore, there was significantly less intraoperative bleeding in the 2team group (30 mL vs. 80 mL, P = 0.004). There was no significant between-group difference in postoperative complications. The incidence of postoperative urinary disturbance was satisfactory at 5% in both groups. CONCLUSIONS: The operation time for LLND performed by a robotic-assisted transabdominal approach was shortened when supported by a transanal approach. The frequency of postoperative urinary disturbance was low in both groups. Therefore, robotic-assisted abdominal LLND supported by a transanal approach can be considered a promising treatment option for advanced low rectal cancer.

Is survival after transanal total mesorectal excision (taTME) worse than that after traditional total mesorectal excision? A retrospective propensity score-adjusted cohort study.

PURPOSE: Transanal total mesorectal excision (taTME) was developed to provide better vision during resection of the mesorectum. Conflicting results have shown an increase in local recurrence and shorter survival after taTME. This study compared the outcomes of taTME and abdominal (open, laparoscopic, robotic) total mesorectal excision (abTME). METHODS: Patients who underwent taTME or abTME for stages I-III rectal cancer and who received an anastomosis were included. A retrospective analysis of a prospectively conducted database was performed. The primary endpoints were overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS). Risk factors were adjusted by propensity score matching (PSM). The secondary endpoints were local recurrence rates and combined poor pathological outcomes. RESULTS: From 2012 to 2020, a total of 189 patients underwent taTME, and 119 underwent abTME; patients were followed up for a mean of 54.7 (SD 24.2) and 78.4 (SD 34.8) months, respectively (p < 0.001). The 5-year survival rates after taTME and abTME were not significantly different after PSM: OS: 78.2% vs. 88.6% (p = 0.073), CSS: 87.4% vs. 92.1% (p = 0.359), and DFS: 69.3% vs. 80.9% (p = 0.104), respectively. No difference in the local recurrence rate was observed (taTME, n = 10 (5.3%); abTME, n = 10 (8.4%); p = 0.280). Combined poor pathological outcomes were more frequent after abTME (n = 36, 34.3%) than after taTME (n = 35, 19.6%) (p = 0.006); this difference was nonsignificant according to multivariate analysis (p = 0.404). CONCLUSION: taTME seems to be a good treatment option for patients with rectal cancer and is unlikely to significantly affect local recurrence or survival. However, further investigations concerning the latter are warranted. TRIAL REGISTRATION: ClinicalTrials.gov (NCT0496910).

Exfoliate cancer cell analysis in rectal cancer surgery: comparison of laparoscopic and transanal total mesorectal excision, a pilot study.

PURPOSE: Minimally invasive surgery (MIS) is currently the standard treatment for rectal cancer. However, its limitations include complications and incomplete total mesorectal resection (TME) due to anatomical features and technical difficulties. Transanal TME (TaTME) has been practiced since 2010 to improve this, but there is a risk of local recurrence and intra-abdominal contamination. We aimed to analyze samples obtained through lavage to compare laparoscopic TME (LapTME) and TaTME. METHODS: From June 2020 to January 2021, 20 patients with rectal cancer undergoing MIS were consecutively and prospectively recruited. Samples were collected at the start of surgery, immediately after TME, and after irrigation. The samples were analyzed for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) through a quantitative real-time polymerase chain reaction. The primary outcome was to compare the detected amounts of CEA and CK20 immediately after TME between the surgical methods. RESULTS: Among the 20 patients, 13 underwent LapTME and 7 underwent TaTME. Tumor location was lower in TaTME (7.3 cm vs. 4.6 cm, P=0.012), and negative mesorectal fascia (MRF) was more in LapTME (76.9% vs. 28.6%, P=0.044). CEA and CK20 levels were high in 3 patients (42.9%) only in TaTME. There was 1 case of T4 with incomplete purse-string suture and 1 case of positive MRF with dissection failure. All patients were followed up for an average of 32.5 months without local recurrence. CONCLUSION: CEA and CK20 levels were high only in TaTME and were related to tumor factors or intraoperative events. However, whether the detection amount is clinically related to local recurrence remains unclear.

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.

Transanal Total Mesorectal Excision for Rectal Cancer: Toward Standardization of the Surgical Technique.

Laparoscopic surgery is widely used for rectal cancer; however, this technique is challenging due to tapering of the mesorectum in the pelvis, and the forward angle of the distal rectum, which renders this part of the rectum less accessible from the abdominal cavity. Hence, concerns regarding its safety and curability have been raised, particularly for inadequate distal and circumferential resection margins. Recently, transanal total mesorectal excision (TaTME), which involves endoscopic total mesorectal excision (TME) retrogradely from the anal side, has attracted attention worldwide as a solution to these problems. TaTME is superior to the conventional laparoscopic approach for rectal cancer in terms of both oncological and functional preservations. However, a shallow learning curve caused by the unfamiliar anatomical view from the anal side can pose challenges. Therefore, an efficient educational system needs to be established. Randomized controlled trials comparing conventional laparoscopic TME with TaTME are ongoing to demonstrate the usefulness of TaTME. This article reviews changes in the surgical treatment of rectal cancer, with a focus on TaTME, and describes the indications, surgical techniques, and training curricula for TaTME.

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.

Comparing perioperative and oncological outcomes of transanal and laparoscopic total mesorectal excision for rectal cancer: a meta-analysis of randomized controlled trials and prospective studies.

INTRODUCTION: Meta-analysis of the results of transanal total mesorectal excision (taTME) and laparoscopic TME (laTME) regarding perioperative and oncological outcomes have been conducted. Due to the lack of high-quality randomized controlled trials (RCTs) and prospective studies in the included literature, the conclusions are unreliable. This study included RCTs and prospective studies for analysis to obtain more reliable conclusions. MATERIALS AND METHODS: Systematic searches of the PubMed, Embase, and Cochrane Library databases were conducted up to June 2023. To assess the quality, the Cochrane quality assessment tool and the Newcastle-Ottawa Scale were employed. The perioperative and oncological outcomes were then analyzed. The I2 statistic was used to evaluate statistical heterogeneity and sensitivity analyses was conducted. RESULTS: A total of 22 studies, comprising 5056 patients, were included in the analysis, of which 6 were RCTs and 16 were prospective studies. The conversion rate in the taTME group was significantly lower than that in the laTME group (OR 0.14, 95% CI 0.09 to 0.22, P < 0.01), and the circumferential resection margin (CRM) was longer (MD 0.99 mm, 95% CI 0.66 to 1.32 mm, P < 0.01), with a lower rate of positive CRM involvement (OR 0.68, 95% CI 0.47 to 0.97, P = 0.03). No statistically significant differences were found in terms of the operation time, intraoperative blood loss, complications, anastomotic leakage, uroschesis, obstruction, secondary operation, hospital stay, urethral injury, readmission, mortality rate within 30 days, mesorectal resection quality, number of harvested lymph nodes, distal resection margin (DRM), positive DRM, local recurrence, and distance recurrence (P > 0.05). CONCLUSION: According to the findings of this meta-analysis, which is based on RCTs and prospective studies, taTME appears to have an advantage over laTME in terms of conversion rate and CRM involvement.

Multicenter phase II trial of transanal total mesorectal excision for rectal cancer: preliminary results.

BACKGROUND: Transanal TME (taTME) combines abdominal and transanal dissection to facilitate sphincter preservation in patients with low rectal tumors. Few phase II/III trials report long-term oncologic and functional results. We report early results from a North American prospective multicenter phase II trial of taTME (NCT03144765). METHODS: 100 patients with stage I-III rectal adenocarcinoma located ≤ 10 cm from the anal verge (AV) were enrolled across 11 centers. Primary and secondary endpoints were TME quality, pathologic outcomes, 30-day and 90-day outcomes, and stoma closure rate. Univariable regression analysis was performed to assess risk factors for incomplete TME and anastomotic complications. RESULTS: Between September 2017 and April 2022, 70 males and 30 females with median age of 58 (IQR 49-62) years and BMI 27.8 (IQR 23.9-31.8) kg/m2 underwent 2-team taTME for tumors located a median 5.8 (IQR 4.5-7.0) cm from the AV. Neoadjuvant radiotherapy was completed in 69%. Intersphincteric resection was performed in 36% and all patients were diverted. Intraoperative complications occurred in 8% including 3 organ injuries, 2 abdominal and 1 transanal conversion. The 30-day and 90-day morbidity rates were 49% (Clavien-Dindo (CD) ≥ 3 in 28.6%) and 56% (CD ≥ 3 in 30.4% including 1 mortality), respectively. Anastomotic complications were reported in 18% including 10% diagnosed within 30 days. Higher anastomotic risk was noted among males (p = 0.05). At a median follow-up of 5 (IQR 3.1-7.4) months, 98% of stomas were closed. TME grade was complete or near complete in 90%, with positive margins in 2 cases (3%). Risk factors for incomplete TME were ASA ≥ 3 (p = 0.01), increased time between NRT and surgery (p = 0.03), and higher operative blood loss (p = 0.003). CONCLUSION: When performed at expert centers, 2-team taTME in patients with low rectal tumors is safe with low conversion rates and high stoma closure rate. Mid-term results will further evaluate oncologic and functional outcomes.

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.

A Cost Overview of Minimally Invasive Total Mesorectal Excision in Rectal Cancer Patients: A Population-based Cohort in Experienced Centres.

Background: Total mesorectal excision has been the gold standard for the operative management of rectal cancer. The most frequently used minimally invasive techniques for surgical resection of rectal cancer are laparoscopic, robot-assisted, and transanal total mesorectal excision. As studies comparing the costs of the techniques are lacking, this study aims to provide a cost overview. Method: This retrospective cohort study included patients who underwent total mesorectal resection between 2015 and 2017 at 11 dedicated centers, which completed the learning curve of the specific technique. The primary outcome was total in-hospital costs of each technique up to 30 days after surgery including all major surgical cost drivers, while taking into account different team approaches in the transanal approach. Secondary outcomes were hospitalization and complication rates. Statistical analysis was performed using multivariable linear regression analysis. Results: In total, 949 patients were included, consisting of 446 laparoscopic (47%), 306 (32%) robot-assisted, and 197 (21%) transanal total mesorectal excisions. Total costs were significantly higher for transanal and robot-assisted techniques compared to the laparoscopic technique, with median (interquartile range) for laparoscopic, robot-assisted, and transanal at €10,556 (8,642;13,829), €12,918 (11,196;16,223), and € 13,052 (11,330;16,358), respectively (P < 0.001). Also, the one-team transanal approach showed significant higher operation time and higher costs compared to the two-team approach. Length of stay and postoperative complications did not differ between groups. Conclusion: Transanal and robot-assisted approaches show higher costs during 30-day follow-up compared to laparoscopy with comparable short-term clinical outcomes. Two-team transanal approach is associated with lower total costs compared to the transanal one-team approach.

Simple transanal total mesorectal resection versus laparoscopic transabdominal total mesorectal resection for the treatment of low rectal cancer: a single-center retrospective case-control study.

Aim: To evaluate the efficacy and safety of simple TaTNE in the treatment of low rectal cancer compared with laparoscopic transabdominal TME. Methods: We collected patients with low rectal cancer admitted to our hospital between January 2019 and November 2021 who received simple TaTME or laparoscopic transabdominal TME. The main outcome was the integrity of the TME specimen. Secondary outcomes were the number of lymph nodes dissected, intraoperative blood loss, operative time, surgical conversion rate, Specimen resection length, circumferential margin (CRM), and distal resection margin (DRM), complication rate. In addition, the Wexner score and LARS score of fecal incontinence were performed in postoperative follow-up. Results: Pathological tissues were successfully resected in all patients. all circumferential margins of the specimen were negative. Specimen resection length was not statistically significant (9.94 ± 2.85 vs. 8.90 ± 2.49, P > 0.05). The incidence of postoperative complications in group A (n = 0) was significantly lower than that in group B (n = 3) (P > 0.05). There was no significant difference in operation time between group A and group B (296 ± 60.36 vs. 305 ± 58.28, P > 0.05). Among the patients with follow-up time less than 1 year, there was no significant difference in Wexner score and LARS score between group A and group B (P > 0.05). However, in patients who were followed up for more than 1 year, the Wexner score in group A (9.25 ± 2.73) was significantly lower than that in group B (17.36 ± 10.95) and was statistically significant (P < 0.05). Conclusion: For radical resection of low rectal cancer, Simple TaTME resection may be as safe and effective as laparoscopic transabdominal TME, and the long-term prognosis may be better.

A systematic review and meta-analysis of minimally invasive total mesorectal excision versus transanal total mesorectal excision for mid and low rectal cancer.

Background: Minimally invasive total mesorectal excision (MiTME) and transanal total mesorectal excision (TaTME) are popular trends in mid and low rectal cancer. However, there is currently no systematic comparison between MiTME and TaTME of mid and low-rectal cancer. Therefore, we systematically study the perioperative and pathological outcomes of MiTME and TaTME in mid and low rectal cancer. Methods: We have searched the Embase, Cochrane Library, PubMed, Medline, and Web of Science for articles on MiTME (robotic or laparoscopic total mesorectal excision) and TaTME (transanal total mesorectal excision). We calculated pooled standard mean difference (SMD), relative risk (RR), and 95% confidence intervals (CIs). The protocol for this review has been registered on PROSPERO (CRD42022374141). Results: There are 11010 patients including 39 articles. Compared with TaTME, patients who underwent MiTME had no statistical difference in operation time (SMD -0.14; CI -0.31 to 0.33; I2=84.7%, P=0.116), estimated blood loss (SMD 0.05; CI -0.05 to 0.14; I2=48%, P=0.338), postoperative hospital stay (RR 0.08; CI -0.07 to 0.22; I2=0%, P=0.308), over complications (RR 0.98; CI 0.88 to 1.08; I2=25.4%, P=0.644), intraoperative complications (RR 0.94; CI 0.69 to 1.29; I2=31.1%, P=0.712), postoperative complications (RR 0.98; CI 0.87 to 1.11; I2=16.1%, P=0.789), anastomotic stenosis (RR 0.85; CI 0.73 to 0.98; I2=7.4%, P=0.564), wound infection (RR 1.08; CI 0.65 to 1.81; I2=1.9%, P=0.755), circumferential resection margin (RR 1.10; CI 0.91 to 1.34; I2=0%, P=0.322), distal resection margin (RR 1.49; CI 0.73 to 3.05; I2=0%, P=0.272), major low anterior resection syndrome (RR 0.93; CI 0.79 to 1.10; I2=0%, P=0.386), lymph node yield (SMD 0.06; CI -0.04 to 0.17; I2=39.6%, P=0.249), 2-year DFS rate (RR 0.99; CI 0.88 to 1.11; I2=0%, P = 0.816), 2-year OS rate (RR 1.00; CI 0.90 to 1.11; I2=0%, P = 0.969), distant metastasis rate (RR 0.47; CI 0.17 to 1.29; I2=0%, P = 0.143), and local recurrence rate (RR 1.49; CI 0.75 to 2.97; I2=0%, P = 0.250). However, patients who underwent MiTME had fewer anastomotic leak rates (SMD -0.38; CI -0.59 to -0.17; I2=19.0%, P<0.0001). Conclusion: This study comprehensively and systematically evaluated the safety and efficacy of MiTME and TaTME in the treatment of mid to low-rectal cancer through meta-analysis. There is no difference between the two except for patients with MiTME who have a lower anastomotic leakage rate, which provides some evidence-based reference for clinical practice. Of course, in the future, more scientific and rigorous conclusions need to be drawn from multi-center RCT research. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO, identifier CRD42022374141.

Transanal total mesorectal excision versus laparoscopic intersphincteric resection for low rectal cancer: a propensity score matching analysis.

BACKGROUND: Anus-preserving surgery for low rectal cancer has always been a serious difficulty for surgeons. Transanal total mesorectal excision (TaTME) and laparoscopic intersphincteric resection (ISR) are commonly used Anus-preserving surgeries for low rectal cancer. The aim of this study was to compare the clinical use of two surgical methods. METHODS: A total of 152 patients with low rectal cancer were treated with taTME in 75 cases and ISR in 77 cases. After propensity score matching, 46 patients in each group were included in the study. Perioperative outcomes, anal function scores (Wexner incontinence score) and quality of life scores (EORTC QLQ C30, EORTC QLQ CR38) at least 1 year after surgery were compared between the two groups. RESULTS: There were no significant differences between the two groups in terms of surgical outcomes, pathological examination of surgical specimens, postoperative recovery, and postoperative complications, except for patients in the taTME group who had their indwelling catheters removed later. Anal Wexner incontinence score was lower in taTME group than ISR group (P < 0.05). On the EORTC QLQ-C30 scale, the physical function and role function scores in the ISR group were lower than those in the taTME group (P < 0.05), while the fatigue, pain symptoms, and constipation scores in the ISR group were higher than those in the taTME group (P < 0.05). On the EORTC QLQ-CR38 scale, the scores of gastrointestinal symptoms and defecation problems in the ISR group were higher than those in the taTME group (P < 0.05). CONCLUSION: Compared with ISR surgery, taTME surgery is comparable in terms of surgical safety and short-term efficacy, and has better long-term anal function and quality of life. From the perspective of long-term anal function and quality of life, taTME surgery is a better surgical method for the treatment of low rectal cancer.