Post-endoscopy colorectal cancer after colectomy in inflammatory bowel disease patients: a population-based register study.

Objectives: Long-standing inflammatory bowel disease (IBD) colitis is an indication for endoscopic surveillance. Postcolonoscopy colorectal cancer (PCCRC), cancer detected after a negative colonoscopy, is a quality indicator for colonoscopy. In analogy with PCCRC, we aimed to assess postendoscopy CRC (PECRC) in individuals with IBD who had undergone colectomy.

Methods: This register study included Swedish adults with an IBD diagnosis who had undergone colectomy and later were examined by either colonoscopy or sigmoidoscopy during 2001-2012. The final study population had a CRC diagnosis within 36 months of the index examination. Poisson regression was used to assess the relative risks (RR) of PECRC.

Results: A total of 33 individuals, 12 with an ileorectal anastomosis and 21 with a rectal remnant, had a CRC diagnosis within 36 months of the index endoscopy. Eleven cancers were detected as CRCs, and 22 (67%) were PECRCs. Compared with individuals aged >70 years, individuals aged <30 years had an RR of 3.1 (P = 0.054) and individuals aged 30-50 years had a RR of 2.6 (P = 0.030). A longer interval between colectomy and index endoscopy (>10 vs. <10 years) was associated with a lower risk of PCCRC (RR = 0.5; P = 0.007). There was no significant difference between the risk for Crohn's disease vs. ulcerative colitis, or between ileorectal anastomosis and rectal remnant risks.

Conclusions: Continuous surveillance of IBD patients after colectomy is important. In the postcolectomy context, PECRC may be used as a quality indicator.