QS131 - The Learning Curve and Implications of Transanal Total Mesorectal Excision for Rectal Cancer: The Canadian taTME Collaboration (CaTaCO) Experience

Sunday, June 2, 2024

1:48 PM – 1:51 PM ET, USA

Location: Room 327

Quick Shot Presenter(s)

Wenjie Lin, MD, FRCS (Ed) (he/him/his)

Consultant
Singapore General Hospital
Duke-NUS Medical School
Vancouver, BC, Canada

All relevant financial disclosures have been managed and will be listed below.
This individual has no financial relationships with ineligible companies.

Senior Author(s)

Carl Brown, MD

Professor
St. Paul's Hospital, University of British Columbia
University of British Columbia
Vancouver, BC, Canada

All of the relevant financial relationships listed below have been mitigated.
This individual has no relevant relationships with ineligible companies.

Author(s)

Antonio Caycedo-Marulanda, MD MSc FRCS FACS FASCRS

Chair Colorectal Surgery
Orlando Health Colon and Rectal Institute
University of Central Florida, Queen's University (CAN)
Orlando, FL, United States

All relevant financial disclosures have been managed and will be listed below.
This individual has no financial relationships with ineligible companies.
PS

Peter Stotland, MD FRCSC

Assistant Professor
University of Toronto
Toronto, Ontario, Canada

Disclosure information not submitted.
UH

Usmaan Hameed, MD FRCSC

Assistant Professor
University of Toronto
Toronto, Ontario, Canada

Disclosure information not submitted.
FL

François Letarte, MD MHSC

Colorectal surgeon
CHU de Quebec
Québec, Quebec, Canada

Disclosure information not submitted.
SD

Sébastien Drolet, MD FRSCS FACS

Colorectal surgeon, assistant professor
CHU de Quebec Universite Laval
Quebec city, Quebec, Canada

Disclosure information not submitted.
SA

Shady Ashamalla, MD

Surgeon
University of Toronto
Toronto, Ontario, Canada

Disclosure information not submitted.
SC

Sami A. Chadi, MD MSc FRCSC FACS FASCRS

Colorectal surgeon
University of Toronto
Toronto, Ontario, Canada

Disclosure information not submitted.
EV

Elena Vikis, MD

Surgeon
University of British Columbia
New Westminster, British Columbia, Canada

Disclosure information not submitted.
A. Sender Sender Liberman, MD

Colorectal Surgeon
McGill University Health Centre
Montreal, Quebec, Canada

Disclosure information not submitted.
GM

George Melich, MD

Surgeon
University of British Columbia
New Westminster, British Columbia, Canada

Disclosure information not submitted.
MR

Manoj Raval, MD, MSc, FRCSC

Colorectal Surgeon
St. Paul's Hospital, University of British Columbia
Vancouver, British Columbia, Canada

Disclosure information not submitted.
FQ

Fayez Quereshy, MD, MBA, FRCSC, FACS

Surgical Oncologist
University of Toronto
Toronto, Ontario, Canada

Disclosure information not submitted.
LL

Lawrence Lee, MD PhD

Associate Professor of Surgery
McGill University Health Centre
Montreal, Quebec, Canada

Disclosure information not submitted.

Purpose/Background: Transanal TME (TaTME) was first described in 2010 as a technique to overcome technical difficulties of the distal pelvis. There were previously concerns over the oncological safety of the procedure, but this has largely been refuted. However, TaTME still is a technically demanding procedure with emphasis on adequate training and safe adoption. Existing literature of 8 studies have estimated this learning curve to be between 50-95 cases. This study aims to present the learning curves and safety of TaTME based on results from 8 centers across Canada.

Methods/Interventions: CaTaCO is a multi-centre prospective cohort involving 8 high-volume rectal cancer academic institutions from across Canada. All consecutive patients with primary rectal cancer treated by TaTME between January 2014 and December 2018 were included, and these represented the first cases of TaTME performed by the participating centres. The primary outcome of interest was the number of surgeries required to decrease the mean operative time and secondary outcome was the number of surgeries required to minimize failure of the procedure defined by a composite outcome consisting of TME quality, conversion, positive surgical margins (CRM/distal margin) and major post operative complications. A risk-adjusted cumulative sum (CUSUM) analysis was used to derive the learning curves.

Results/Outcomes: 608 patients underwent TaTME across 8 centers. Risk-adjusted CUSUM analysis of operative times estimated 66, 79, 43 and 61 cases to reach proficiency in the high volume (>100 cases) centres. Low volume centres ( < 60 cases) did not show curves reaching proficiency. Risk-adjusted CUSUM analysis of composite outcome showed minimization of failure of procedure occurred at 97, 101, 105 and 62 cases respectively.
Patients were subsequently divided into 2 groups: before (n=249) and after overcoming the learning curves (n=214). Group 2 had significantly higher number of patients who had undergone neoadjuvant chemoradiation (RR 1.1, 95% CI 1.0-1.3, p=0.03), and patients who underwent abdominoperineal resection or pelvic exenteration (vs low anterior resection) (RR 2.0, 95% CI 1.1-3.5, p=0.02). In terms of outcomes, group 2 had a lower major complication rate (RR 0.6 95% CI 0.4-1.0, p=0.05), lower anastomotic leak rate (RR 0.4, 95% CI 0.2-0.8, p=0.01), lower rate of pelvic abscess (RR 0.5, 0.3-1.0, p=0.05), lower rates of urinary tract infections (RR 0.2, 95% CI 0.04-0.9, p=0.01), and lower rates of failure of procedure based on composite outcome (RR 0.7, 95% CI 0.5-0.9, p=0.02).

Conclusion/Discussion: TaTME is a technically demanding procedure with a relatively long learning curve of between 43-79 cases for proficiency; “mastery” of the procedure measured by minimization of failure based on the composite outcome occurred at 63-105 cases, based on our results. This is in line with published literature with learning curves between 51-95 cases. There is a corresponding reduction of major complications and anastomotic leaks after the learning curve is crossed, in spite of an increase in cases with neoadjuvant chemoradiation. Of note, the rates of perioperative events even during the learning phase fall within benchmarked accepted rates of complications, suggesting that safe adoption of TaTME is possible in high volume centers.