Patients undergoing total colectomy for inflammatory bowel disease (IBD) may develop cancer in the rectal remnant, but the association is poorly understood.
To examine risk and prognosis of rectal cancer after total colectomy for IBD.
Nationwide population-based study.
Denmark 1977-2013.
Patients with IBD undergoing total colectomy.
We examined incidence of rectal cancer among patients with IBD and total colectomy and compared cancer stage to that of other rectal cancer patients in Denmark. We used Kaplan-Meier methodology to estimate survival and Cox regression to estimate adjusted mortality rate ratios (aMRRs) following a rectal cancer diagnosis, comparing patients with and without IBD and a rectal remnant.
We identified 4,703 patients with IBD (1,026 Crohn’s disease; 3,677 ulcerative colitis) who underwent total colectomy with a rectal remnant. During 29,725 years of follow-up, 30 rectal cancers were observed, compared to 8 expected [standardized incidence ratio (SIR)=3.6, (95% confidence interval (CI): 2.4-5.1)]. Cancer stage distributions were similar. Risk of rectal cancer 35 years after total colectomy was 1.9% (95% CI:1.1%-2.9%). Five years after rectal cancer diagnosis, survival was 28% (95% CI: 12%-47%) and 38% (95% CI: 37%-38%) for patients with and without IBD and a rectal remnant, respectively. The aMRR 1-5 years after a rectal cancer diagnosis was 2.5 (95% CI: 1.6-3.9). Median time from last recorded non-diagnostic proctoscopy to rectal cancer diagnosis for patients with IBD and total colectomy was 1.1 years.
Few outcomes, use of administrative and not clinical data.
Long-term risk of rectal cancer following total colectomy for IBD was low. Survival following a diagnosis of rectal cancer was poorer for patients with IBD and total colectomy than for rectal cancer patients without IBD and total colectomy. Endoscopic surveillance, as it appeared to be practiced in this cohort, may be inadequate. See Video Abstract at .