Sylla, P.

Introduction With the rapidly changing landscape of rectal cancer treatment, it is becoming increasingly challenging for clinicians to interpret and synthesise the vast amount of high-quality evidence being generated. A core outcome set (COS) for clinical trials in rectal cancer would help address issues surrounding outcome selection and reporting. The purpose of this research project is to develop a COS to be used in research comparing different treatment paradigms in the management of rectal cancer. Methods and analysis This will be a mixed-methods project, including a systematic review, semi-structured interviews and a Delphi consensus process. The project was designed in accordance with the COMET (Core Outcome Measures in Effectiveness Trials) Handbook, which provides a framework for COS development based on existing evidence. A multidisciplinary Study Advisory Group, composed of rectal cancer providers, methodologists and patients, will oversee the project. A systematic review will be performed to identify an inclusive list of outcomes reported by researchers in previous rectal cancer trials. Outcomes will be collapsed into various core areas and domains according to the OMERACT Filter V.2.0. Semi-structured interviews with rectal cancer survivors and their partners/caregivers will help identify additional patient-centric outcomes not captured in the systematic review. Finally, after a final list of outcomes is generated, patients and healthcare professionals will be invited to participate in a Delphi process to develop the final COS. Ethics and dissemination The study has received full approval with the Research Ethics Committee at the Integrated Health and Social Services Network for West-Central Montreal (health network responsible for the Jewish General Hospital) (REC: 2025-4377) and the Institutional Review Board of the Mount Sinai School of Medicine (IRB: STUDY-25-00515). The results of this study will be presented at national and international meetings and a manuscript will be submitted for publication in a high-impact surgery and/or oncology peer-reviewed journal. Trial registration number The study was registered in the COMET database in December 2023 ( https://www.comet-initiative.org/Studies/Details/2941 ). The full systematic review protocol, along with the search strategy and inclusion/exclusion criteria, was registered online in September 2023 (researchregistry.com; reviewregistry1705).

Background: Transanal total mesorectal excision (taTME) facilitates sphincter preservation in low rectal cancer. Preliminary results and functional outcomes from the North American multicenter phase II taTME trial (NCT03144765) have been published. Three-year outcomes are reported. Methods: Patients with stage I to III rectal adenocarcinoma were enrolled across 11 centers (2017–2022). Endpoints included TME grade, 3-year overall survival, disease-free survival, cancer-specific survival, recurrence, late (beyond 90 d) complications, and stoma-free survival. Surveillance followed National Comprehensive Cancer Network guidelines, with pelvic magnetic resonance imaging (MRI) at 3 years to assess for pelvic sidewall recurrence when possible. Kaplan–Meier analysis assessed oncologic outcomes. Results: One hundred patients underwent taTME for tumors at a median of 5.8 cm from the anal verge, with intersphincteric resection in 36% and handsewn anastomosis in 54%. Median follow-up was 50.9 months. Late complications occurred in 32 patients, including 21 severe (Clavien-Dindo ≥3). Late anastomotic complications occurred in 5 patients; one required surgical revision. Estimated 3-year overall survival, cancer-specific survival, and disease-free survival were 93.7%, 96.6%, and 84.6%, respectively. Distant recurrence occurred in 15 patients (median: 17.6 months), most commonly in the lung and liver. Locoregional recurrence occurred in 2 patients. Preoperative N stage, lymph node yield, tumor deposits, and perineural invasion were associated with recurrence. Among 100 patients diverted at taTME, 97% were stoma-free at 3 years; 4 patients later underwent secondary diversion. Conclusions: Three-year outcomes of this multicenter trial support the safety and efficacy of taTME in resectable mid and low rectal tumors, with outcomes comparable to contemporary studies. Longer-term oncologic and functional outcomes are needed.