Incidence of Colorectal Cancer and Extracolonic Cancers in Veteran Patients With Inflammatory Bowel Disease.

BACKGROUND

The risk for colorectal cancer (CRC) and certain extracolonic cancers is thought to be increased in inflammatory bowel disease (IBD), but few recent US studies have evaluated this issue. We aimed to estimate the incidence of CRC and extracolonic cancers in IBD patients.

METHODS

In this case-control study, cases were all IBD patients treated in our Department of Veterans Affairs (VA) hospital who developed CRC or extracolonic cancers between 1996 and 2015. Controls were patients in the general VA population who developed these cancers during the same time. We compared cancer incidence rates (IRs) in cases and controls.

RESULTS

There was no significant difference between cases and controls in the 20-year IR for CRC (148/100 000 in IBD patients, 97/100 000 in controls; relative risk [RR], 1.53; 95% confidence interval [CI], 0.86-2.69). In contrast, IBD cases had a significantly higher 20-year IR for all extracolonic cancers than controls (2839/100 000 in IBD patients, 1960/100 000 in controls; RR, 1.45; 95% CI, 1.27-1.65). Site-specific analyses revealed that IBD patients had significantly elevated risks for nonmelanoma skin cancers (RR, 2.38; 95% CI, 1.99-2.85), melanoma skin cancers (RR, 2.85; 95% CI, 1.63-4.88), renal tumors (RR, 2.90; 95% CI, 1.46-5.84), prostate cancer (RR, 1.70; 95% CI, 1.28-2.27), and pancreatic cancer (RR, 4.23; 95% CI, 1.35-13.29).

CONCLUSIONS

The incidence of CRC was not significantly higher in our veteran patients with IBD than in control patients in the general VA population. In contrast, our IBD patients had a significantly higher risk for extracolonic cancers than controls, including cancers of the skin, kidneys, prostate, and pancreas. 10.1093/ibd/izx046_video1Video 1.izx046_Mosher_Video5734484616001.