Mesalamine protects against colorectal cancer in inflammatory bowel disease.

Background: Individuals with inflammatory bowel disease (IBD) are at increased risk of developing colorectal cancer (CRC) compared with the general population. Previous studies show this risk is strongly associated with dysplasia, extent of disease, duration of disease, and degree of inflammation, while chemoprevention of CRC has less support.

Aim: Evaluate factors influencing risk of colorectal cancer development in inflammatory bowel disease patients.

Methods: IBD patients with CRC were matched to controls by IBD type, age at diagnosis, sex, race, extent of disease, and disease duration. We compared body mass index, family history of IBD, family history of CRC, tobacco use, and cumulative and daily use of aminosalicylates, immunomodulators, folic acid, steroids, and nonsteroidal anti-inflammatory drugs. Statistical analysis was performed with logistic regression and receiver operating characteristic (ROC) curves.

Results: Of 1,594 IBD patients, 30 CRC patients were identified. Of these, 18 CRC patients were matched to 30 controls. More control patients used a cumulative aminosalicylate dose of >or=4,500 g (46.6% versus 5.6%; P = 0.047), folic acid (40.0% versus 16.7%; P = 0.002), cumulative folic acid dose of >or=1,400 mg (30.0% versus 11.1%; P = 0.014), and average daily folic acid dose of >or=1 mg (30.0% versus 16.7%; P = 0.002) compared with CRC patients. Multivariate analysis showed that a cumulative aminosalicylate dose of >or=4,500 g reduced the risk of CRC by 97.6% (P = 0.047). Folic acid reduced CRC risk by 89% (P = 0.002).

Conclusions: Aminosalicylate and folic acid use may decrease the risk of CRC among IBD patients.