Colorectal cancer is one of the leading causes of cancer death. Most colorectal cancers are believed to develop from colorectal adenomas. We examined the effect of the selective cyclooxygenase-2 inhibitors rofecoxib and celecoxib, nonselective nonsteroidal anti-inflammatory drugs, aspirin, and acetaminophen on colorectal neoplasia (colorectal cancer, colorectal adenoma, or both).

This was a nested case-control study, which used data from a government insurance database on patients 65 years and older who underwent a diagnostic test or procedure for colorectal neoplasia between January and June 2001. Logistic regression models were used to determine the effect of exposure to the drugs of interest for at least 3 months on the occurrence or recurrence of colorectal neoplasia.

The control group included 2568 patients found to be free of colorectal neoplasia; 730 patients were diagnosed with colorectal adenoma, and 179 were diagnosed with colorectal cancer. Patients more likely to have colorectal adenoma (odds ratio, 95% confidence interval) were those diagnosed with colorectal adenoma (4.12, 3.27–5.18) or colorectal cancer (3.74, 2.32–6.03) in the previous 1–3 years and those with hemorrhage of the rectum or unspecified anemia in the prior month (3.19, 2.46–4.12). Exposures to rofecoxib (0.67, 0.46–0.98) and nonselective nonsteroidal anti-inflammatory drugs (0.41, 0.21–0.83) reduced the risk of colorectal adenoma. Rofecoxib, celecoxib, and nonselective nonsteroidal anti-inflammatory drugs were all protective against both neoplasias (0.64, 0.45–0.91; 0.73, 0.54–0.99; and 0.47, 0.26–0.86, respectively).

Rofecoxib, celecoxib, and nonselective nonsteroidal anti-inflammatory drugs seem to protect against the development of colorectal neoplasia.