February 22, 2022
What is the risk of rectal cancer following proximal fecal diversion or subtotal colectomy?
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; https://doi.org/10.1093/ecco-jcc/jjab090
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
Allocation: Not applicable
Level of Evidence: 2b