"We found that statin-takers cut their risk for advanced disease in half," says Elizabeth Platz, Sc.D., M.P.H., assistant professor at the Johns Hopkins Bloomberg School of Public Health and Kimmel Cancer Center.
Although earlier, smaller studies have linked the use of statins to a lower risk of prostate and other cancers, such as breast and colon, this is the first to tie risk reduction to prostate cancer stage while tracking the medication use before study participants got cancer.
Still, the researchers caution that data are not conclusive enough to warrant prescribing the drug to reduce cancer risk alone because many questions still linger, such as how they might contribute to delaying the cancer process more effectively than non-statins.
"Additional large studies may help confirm these results, but we also have some very important questions lingering as to which biochemical processes may link statins and reduced prostate cancer development," says Platz. "Instead of preventing cancer, statins might work by stalling a tumor already in the prostate, helping to ensure that it doesn't get worse."
Platz noted that "when cholesterol-lowering drugs first came onto the market almost 20 years ago, there was even concern that they might increase the risk of cancer. Now, we are seeing more evidence that the opposite may be the case, but more research needs to be done."
Platz is expected to present results of her study at the American Association for Cancer Research (AACR) annual meeting.
In their study, the researchers tracked use of cholesterol-lowering drugs (including statins and non-statins) and prostate cancer diagnosis among a group of 34,438 male health professionals, including dentists and veterinarians.
They found no association between use of cholesterol-lowering drugs and whether or not men were diagnosed with early, curable forms of prostate cancer. But they did find that men who took cholesterol-lowering medications, as opposed to those not taking them, had half the risk of eventually developing advanced prostate cancers (283 men had cancer that invaded nearby tissue, had spread to other parts of the body, or was fatal) and one-third the risk of the most serious type of advanced prostate cancer - fatal and metastatic (206 of the 283 men).
"And the longer men used cholesterol-lowering drugs, the lower their risk," she added.
By the end of the study, more than 90 percent of men taking cholesterol-lowering drugs opted for statins, as opposed to other cholesterol-lowering drugs. "Since most of these study participants were taking statins during the time that we saw the highest levels of risk-reduction, we believe that statins more than any of the other cholesterol-lowering drug may have the biggest risk-reduction effects, but more studies are necessary to validate this," says Platz.
Statins lower cholesterol by blocking an enzyme that controls its assembly. There are clues to suggest key cellular pathways involved in cancer-risk reduction may include statins' effects on testosterone production, cell signaling, and inflammation. Or the drugs may play a role in changing prostate cancer cell membranes, which are rich in cholesterol.
Prostate cancer is the leading cancer in American men. It strikes more than 230,000 U.S. men annually and kills more than 30,000.
Additional research investigators include Michael F. Leitzmann, from the National Cancer Institute; Kala Visvanathan from Johns Hopkins; Meir J. Stampfer, Walter C. Willett, Eric B. Rimm, and Edward Giovannucci from Harvard University.
This research was presented during the 96th Annual Meeting of the American Association for Cancer Research, Abstract #4374.