Objectives: There is increased interest in determining whether 5-aminosalicylate (5-ASA) use can prevent the development of colorectal cancer (CRC) among patients with inflammatory bowel disease (IBD). The aim of this study was to determine whether use of 5-ASA was associated with a reduced risk of CRC in these patients.
Methods: We extracted from our population-based University of Manitoba Inflammatory Bowel Disease Epidemiology Database the number of patients with a new diagnosis of CRC between the years 1997 and 2000. From within our Inflammatory Bowel Disease Epidemiology Database we extracted a control group of IBD patients who did not develop CRC matched to the case group who did develop CRC by age, sex, diagnosis, year of diagnosis, and geographic area of residence. We linked cases and controls with Manitoba Health's Drug Program Information Network to study 5-ASA use within 2 yr before CRC diagnosis. The Drug Program Information Network database is a population-based database that was established in 1995 and that records all prescription drugs.
Results: There were 25 cases of IBD identified as having CRC. These were matched with 348 cases of IBD who did not develop CRC. CRC cases were more likely to be exposed to 5-ASA (odds ratio = 1.46; 95% CI = 0.58-3.73) but this result was not statistically significant. The mean total days of use was 400.9 days +/- 185.9 among CRC cases versus 420.2 days +/- 241.7 among non-CRC cases (p = 0.92). The prescribed daily dose was 2295 mg/day +/- 1041 mg among CRC cases and 1811 mg +/- 520 mg among controls (p = 0.21).
Conclusions: These data do not support 5-ASA as protective in preventing CRC.