Background: Transanal total mesorectal excision (TaTME) has been proposed as an approach in patients with mid and low rectal cancer. The TaTME procedure has been introduced in the Netherlands in a structured training pathway, including proctoring. This study evaluated the local recurrence rate during the implementation phase of TaTME. Methods: Oncological outcomes of the first ten TaTME procedures in each of 12 participating centres were collected as part of an external audit of procedure implementation. Data collected from a cohort of patients treated over a prolonged period in four centres were also collected to analyse learning curve effects. The primary outcome was the presence of locoregional recurrence. Results: The implementation cohort of 120 patients had a median follow up of 21⋅9 months. Short-term outcomes included a positive circumferential resection margin rate of 5⋅0 per cent and anastomotic leakage rate of 17 per cent. The overall local recurrence rate in the implementation cohort was 10⋅0 per cent (12 of 120), with a mean(s.d.) interval to recurrence of 15⋅2(7⋅0) months. Multifocal local recurrence was present in eight of 12 patients. In the prolonged cohort (266 patients), the overall recurrence rate was 5⋅6 per cent (4⋅0 per cent after excluding the first 10 procedures at each centre). Conclusion: TaTME was associated with a multifocal local recurrence rate that may be related to suboptimal execution rather than the technique itself. Prolonged proctoring, optimization of the technique to avoid spillage, and quality control is recommended.

Objective: This study aimed to determine local recurrence (LR) rate and pattern after transanal total mesorectal excision (TaTME) for rectal cancer. Background: TaTME for mid-and low rectal cancer has known a rapid and worldwide adoption. Recently, concerns have been raised on the oncological safety in light of reported high LR rates with a multifocal pattern. Methods: This was a multicenter observational cohort study in 6 tertiary referral centers. All consecutive TaTME cases for primary rectal adenocarcinoma from the first TaTME case in every center until December 2018 were included for analysis. Patients with benign tumors, malignancies other than adenocarcinoma and recurrent rectal cancer, as well as exenterative procedures, were excluded. The primary endpoint was 2-year LR rate. Secondary endpoints included patterns and treatment of LR and histopathological characteristics of the primary surgery. Results: A total of 767 patients were identified and eligible for analysis. Resection margins were involved in 8% and optimal pathological outcome (clear margins, (nearly) complete specimen, no perforation) was achieved in 86% of patients. After a median follow-up of 25.5 months, 24 patients developed LR, with an actuarial cumulative 2-year LR rate of 3% (95% CI 2-5). In none of the patients, a multifocal pattern of LR was observed. Thirteen patients had isolated LR (without systemic disease) and 10/13 could be managed by salvage surgery of whom 8 were disease-free at the end of follow-up. Conclusions and Relevance: This study shows good loco regional control after TaTME in selected cases from tertiary referral centers and does not indicate an inherent oncological risk of the surgical technique.

Patients undergoing laparoscopic or transanal TME showed comparable functional and QOL outcomes. Although the TaTME technique is still evolving, this study indicates that this technique is a safe alternative to laparoscopic surgery in terms of functional outcomes for mid and low rectal cancers.

Table. Pathological Features and Molecular Profile of Early-Onset Colorectal Cancer Pathological features Molecular profile Poor differentiation Microsatellite stability Mucinous tumors More likely to exhibit LINE-1 hypomethylation and TP53 sequence variations Signet-ring morphology Less frequently harbor KRAS, BRAF V600E, and APC sequence variations Perineural/venous invasion Promoter methylation of CpG islands Abbreviations: APC, adenomatous polyposis coli; BRAF, B-Raf; KRAS, K-Ras; LINE-1, long interspersed nuclear elements; TP53, tumor protein 53.

Background Transanal total mesorectal excision (TaTME) is a new complex technique with potential to improve the quality of surgical mesorectal excision for patients with mid and low rectal cancer. The procedure is technically challenging and has shown to be associated with a relative long learning curve which might hamper widespread adoption. Therefore, a national structured training pathway for TaTME has been set up in the Netherlands to allow safe implementation. The aim of this study was to monitor safety and efficacy of the training program with 12 centers. Methods Short-term outcomes of the first ten TaTME procedures were evaluated in 12 participating centers in the Netherlands within the national structured training pathway. Consecutive patients operated during and after the proctoring program for rectal carcinoma with curative intent were included. Primary outcome was the incidence of intraoperative complications, secondary outcomes included postoperative complications and pathological outcomes. Results In October 2018, 12 hospitals completed the training program and from each center the first 10 patients were included for evaluation. Intraoperative complications occurred in 4.9% of the cases. The clinicopathological outcome reported 100% for complete or nearly complete specimen, 100% negative distal resection margin, and the circumferential resection margin was positive in 5.0% of patients. Overall postoperative complication rate was 45.0%, with 19.2% Clavien-Dindo ≥ III and an anastomotic leak rate of 17.3%. Conclusions This study shows that the nationwide structured training program for TaTME delivers safe implementation of TaTME in terms of intraoperative and pathology outcomes within the first ten consecutive cases in each center. However, postoperative morbidity is substantial even within a structured training pathway and surgeons should be aware of the learning curve of this new technique.Keywords TaTME · TAMIS · Rectal cancer · Proctoring · Training Transanal total mesorectal excision (TaTME) has been proposed as a potentially better alternative to the laparoscopic standard TME for mid and distal rectal cancer [1][2][3][4]. The bottom-up approach for the deep pelvic region increases exposure and facilitates the distal mesorectal excision. Especially those difficult cases such as obese patients, low rectal and Other Interventional Techniques Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.