Men who take even small amounts of common cholesterol-lowering drugs such as Lovastatin and Simvastatin reduce their risk of prostate cancer by 65 percent, according to a new Oregon Health & Science University Cancer Institute study published in a recent issue of the American Journal of Epidemiology.
"This study suggests that use of cholesterol-lowering drugs can dramatically reduce a man's risk of prostate cancer, particularly the more aggressive forms. This is significant because prostate cancer is the second leading cause of cancer deaths among U.S. men, and there are few options for prevention," said Jackilen Shannon, Ph.D., R.D., member of the OHSU Cancer Institute, research scientist at the Portland Veterans Affairs Medical Center (PVAMC) and lead author of the study.
Shannon's research shows that men who have been prescribed statins to treat high cholesterol have a 65 percent lower risk of prostate cancer than men who have taken none at all. When the men are analyzed separately according to the severity of their cancer at diagnosis, the association between statin use and prostate cancer prevention is strongest for more severe disease.
"We were interested in the relationship between statin use and prostate cancer because other recent research has demonstrated that in a number of other tumor types, statins also induce cancer cell death and arrest growth. While there is still a lot of work to be done to establish exactly how statins are able to change cancer cells, this is a promising first step," Shannon said.
Shannon and colleagues evaluated the association between statin use and prostate cancer risk in an observational study. One hundred prostate cancer patients were recruited into the study. They had been referred for prostate biopsies at the PVAMC because of elevated prostate-specific antigen (PSA) levels, or abnormal prostate exams. Statin use among these men was recorded and compared to the use of statins among a control group of 202 PVAMC patients whose PSA had been level for a year.
Certain prostate conditions, including prostate cancer, can cause high levels of PSA in the blood. PSA levels are monitored to help predict the presence and progression of prostate cancer. Researchers used the center's electronic pharmacy database to characterize the type of statin prescribed, the duration of use and at what dose. This statin data was merged with demographic data from the main case-control study.
"Because the men in this study were part of a larger study of diet and prostate cancer risk that included extensive diet questionnaires, we were able to consider the possible effect of many different factors, including cholesterol in the diet and total fat and calorie intake, on our statin data," Shannon said. Researchers also adjusted data for age, body mass index and race, use of non-steroidal anti-inflammatory drugs and use of other lipid-lowering drugs.
When statin use was grouped by duration and intensity of use, those who had used statins for the longest period (more than 2.8 years) and at higher doses (average daily dose of more than 40mg/day) reduced their risk the most. These results remained consistent when individual types of statins were analyzed separately.
Shannon notes that while intriguing, these results are from a small study and must be viewed cautiously. Should these findings be replicated in future larger studies or clinical trials, they may provide the necessary evidence to consider statin use for prostate cancer prevention.
"This drug holds the promise of not only reducing the risk of cardiovascular deaths, but prostate cancer as well, the most common cancer in men," said Mark Garzotto, M.D., a cancer researcher with the OHSU Cancer Institute and director of urologic oncology at the PVAMC. "Currently, the data are not mature enough to decide whether statins would prevent prostate cancer, thus more trials are needed. However, men should talk to their doctors about taking statin drugs to see if they would benefit for other reasons like cardioprotection."
This study was funded by the U.S. Public Health Service and the U.S. Department of Veterans Affairs.