Kantonsspital St.Gallen

The sphincter’s fate in low rectum cancer: a decision analysis


Management of low rectal cancer poses a major challenge in terms of tumor control and sphincter preservation. While abdominoperineal resection (APR) is considered the standard of care for rectal cancers within 5 cm from the anal verge, APR entails a permanent colostomy translating into an impaired quality of life, sexual function, and body image.

The gain in rectal cancer survival over the last three decades is largely ascribed to refinements in surgical technique, particularly the promotion of total mesorectum excision and of a clear circumferential margin, together with neoadjuvant therapy. Recently, the importance of a generous distal resection margin has been questioned, while it was recognized that preservation of the upper part of the internal anal sphincter was not necessary for fecal continence. Hence, intersphincteric resection (ISR) was developed as a sphincter sparing approach for low rectum cancer. ISR sacrifices some or the entire internal anal sphincter, but allows for an anastomosis between the colon and the mid anal canal, thus avoiding a permanent colostomy.

ISR is considered for stage I - III rectal cancers. As such, this procedure may allow preservation of the anal sphincter and body image in over 70% of the newly diagnosed rectum cancer. Nonetheless, ISR carries a risk of diminished anal continence and requires a temporary ostomy. Moreover, a local recurrence rate of up to 14% has been reported after ISR, though this had limited influence on overall survival. While further prospective cohort series have established the oncological safety and quality of intestinal function after ISR, no randomized controlled trial has compared APR to ISR. Importantly, a randomized trial comparing a sphincter preserving procedure to amputation and a permanent colostomy is unlikely to be performed, as accrual may prove difficult. Hence, patients and surgeons are left with a difficult dilemma. In this context, decision analysis can help and inform the choice between two competing procedures, placing the patient’s values at the heart of decision-making. Decision analysis uses a formal framework to explicitly address the trade-offs between APR and ISR while quantifying the clinical parameters which affect the decision-making process.

The objective of the present research project is to develop and publish a decision analysis model synthetizing the best available evidence to inform and personalize decision-making when considering surgical treatment of a low rectum cancer.
project partner University of Basel, University of Uppsala, University of Toronto
type of project clinical studies
status completed
start of project 2012
end of project 2013
study design Decision-analysis based on population-wide data from Sweden and on a systematic literature review and Bayesian meta-analysis thereof
responsible person PD Dr med Michel Adamina, MSc