Statins do not reduce risk for colorectal cancer in postmenopausal women

The use of statins among a group of postmenopausal women did not reduce the risk for colorectal cancer, according to the results of a prospective analysis of data from the large population-based Women's Health Initiative (WHI).

"The results of our study are consistent with the majority of the literature suggesting no significant reduction in colorectal cancer risk among users of statins," said Michael S. Simon, M.D., professor of oncology in the department of oncology at Wayne State University and Barbara Ann Karmanos Cancer Institute, Detroit.

Simon presented these study results at the Ninth Annual AACR Frontiers in Cancer Prevention Research Conference, held here from Nov. 7-10, 2010.

According to Simon, the results from several case-control studies have shown a moderate reduction in colorectal cancer risk in people who use statins. However, a majority of the literature researching the association, including data from randomized controlled trials and cohort studies, show no association between statin use and reduced colorectal cancer risk.

"Colorectal cancer is the third leading cause of cancer incidence and death in the United States," he said. "While regular screening has been shown to be effective in decreasing mortality, the majority of the population receives no screening, or inadequate screening, which supports the need to focus on chemoprevention to lower death rates."

One method of colorectal cancer chemoprevention being researched is the use of statins. In this study, Simon and colleagues used data from the WHI to determine if there was a link between colorectal cancer prevention and statins. The study included 159,219 postmenopausal women aged 50 to 79 years. There were 2,000 cases of colorectal cancer identified during an average of 10 years of follow-up.

Women participating in the study were asked to bring all medications to their screening interviews and the use of any statin, or other lipid-lowering medication, was entered into the WHI database. About 8 percent of women in the study were using statins.

The yearly rate of colorectal cancer did not differ between women taking statins and those not taking statins. There was also no difference in risk for colorectal cancer based on the duration of statin use, type of statin, statin potency or use of other lipid-lowering medications. In addition, the researchers identified no link between statin use and tumor location, stage, grade or histology.

According to Simon though, the effect of statins on colorectal cancer risk deserves some additional study in certain patient populations.

"A recent study suggested a possible greater effect of statins in reducing both cardiovascular and colorectal cancer risk among individuals with a genetic variation of the enzyme inhibited by statins," he said. "This finding suggests that future studies should focus on individuals at high risk based on family history or genetic predisposition."