Colorectal cancer prevention in ulcerative colitis: a case‐control study

Abstract

Background: The risk of colorectal cancer (CRC) in ulcerative colitis (UC) increases with extent and duration of disease. Identifying other risk factors would allow targeting of sub‐groups at greatest risk, enabling more cost‐effective surveillance. Methods: We conducted a case‐control study comparing 102 cases of CRC in UC with matched controls. Odds ratios (OR) for cancer risk were estimated by conditional logistic regression. A multivariate model assessed the contribution of individual variables. Results: Regular 5‐aminosalicylic acid (5‐ASA) therapy reduces cancer risk by 75% (OR 0.25, 95% CI: 0.13–0.48, P < 0.00001). Adjusting for other variables, taking mesalazine regularly reduces risk by 81% (OR 0.19, 95% CI: 0.06–0.61, P =0.006) and visiting a hospital doctor more than twice a year also reduces risk (OR 0.16, 95% CI: 0.04–0.60, P =0.007). Considering variables independently, having a family history of sporadic CRC in any relative increases risk fivefold (OR 5.0, 95% CI: 1.10–22.82, P < 0.04). Conclusions: CRC risk among UC patients can be reduced by regular therapy with 5‐ASA medication. Colonoscopic surveillance may be best targeted on those unable to take 5‐ASAs (e.g. due to allergy) and those with a positive family history of CRC.