Rectal cancer in the diverted rectum

Rectal cancer in the diverted rectum

February 22, 2022

Issue 04

Clinical Question

What is the risk of rectal cancer following proximal fecal diversion or subtotal colectomy?

Editor’s Bottom Line

Rectal cancer arises rarely in a rectal stump, but even less often in patients who undergo regular proctoscopy. Surveillance of the rectum in patients with proximal diversion should not be forgotten.


Brar MS, van Overstraeten A de Buck, Baxter NN. Rectal Cancer Incidence is Low Following Rectal Diversion or Subtotal Colectomy for IBD: Results of a Population-based Study. J Crohn’s Colit. 2021;15(11):1787–98;


The incidence of rectal cancer following subtotal colectomy or fecal diversion in patients with medically refractory IBD has been reported to be as low as 2% and as high as 20% within two decades of surgery. In this study researchers retrospectively examined data from a province-wide database in Ontario from 3,700 IBD patients who had undergone either of these surgeries between 1991 and 2015. All patients had a diverted rectum left in situ initially.

Data showed that 47% of patients underwent either completion proctectomy or reversal of diversion, with roughly 80% of those doing so within five years of the initial surgery. Additionally, 0.81% of those with a rectal stump in place were diagnosed with rectal cancer within 10 years (95% Confidence Interval [CI], 0.53%–1.20%) and 1.86% were diagnosed with rectal cancer within 20 years [95% CI, 1.29%–2.61%]. The median time between index surgery and rectal cancer diagnosis was 8.5 years (IQR: 3.1–12.8 years).

Multivariate analysis showed that surveillance endoscopy significantly reduced the risk of rectal cancer (subhazard Ratio [sHR]: 0.37; 95% CI, 0.16–0.82; p=0.014]. Roughly one-third of patients did not undergo adequate surveillance endoscopy, which the authors defined as endoscopy performed at least every five years.  


Study Design: Retrospective population-based cohort

Funding: None

Allocation: Not applicable

Setting: Multicenter

Level of Evidence: 2b