Statins not associated with reduced colorectal cancer risk

Use of cholesterol reducing drugs is not associated with a reduced risk of colorectal cancer, according to a study in the Journal of the National Cancer Institute.

Previous studies have investigated the association between statins, the most commonly used type of cholesterol lowering drug, and colorectal cancer incidence, but these studies have produced mixed results. Several randomized trials, generally considered the most reliable type of study, found no clear association between statin use and colorectal cancer, but these trials were relatively small and did not examine long-term statin use. In contrast, a recent large study, the Molecular Epidemiology of Colorectal Cancer (MECC) study, which included almost 4000 people, showed that statin use for a period of more than 5 years was associated with a 47% reduction in the risk of colorectal cancer.

Eric J. Jacobs, Ph.D., of the American Cancer Society in Atlanta, and colleagues investigated the association between use of cholesterol-lowering drugs and colorectal cancer risk in the 132,136 men and women enrolled in the Cancer Prevention Study II Nutrition Cohort.

Researchers identified 815 cases of colorectal cancer in cohort participants during the period from 1997 to 2001. They found that use of cholesterol-lowering drugs, even use for 5 or more years, was not associated with colorectal cancer incidence.

This study measured use of cholesterol lowering drugs in general rather than use of statins in particular. However, the authors note that if statins strongly reduced the risk of colorectal cancer, use of any cholesterol-lowering drugs would likely have been associated with some reduction in risk because most users of cholesterol lowering drugs use statins.

"Our results do not support the hypothesis that statins, as a class of drugs, strongly reduce risk of colorectal cancer," they write.

In an accompanying editorial, John McLaughlin, Ph.D., of Cancer Care Ontario and the Prosserman Centre for Health Research in Ontario, calls the study a "prompt and timely contribution to the literature, because it capitalized on the existence of a large and well-characterized cohort." He writes that the study results suggest that a clinical trial that evaluates statins as a chemopreventive agent would be premature and that the results show that large cohort studies provide an excellent resource for hypothesis testing.