Statins and prostate cancer

As a group, the six statin drugs are the best-selling prescription medications in the United States. It’s no surprise, since heart disease remains America’s leading cause of death. Statin therapy reduces the risk of heart attacks and other clinical manifestations of coronary artery disease by up to 37%, with most of the benefit going to men at high risk.

All the statins lower LDL (“bad”) cholesterol by inhibiting HMG-CoA reductase, the enzyme that liver cells use to manufacture cholesterol. The drugs also trick the liver into removing cholesterol from the bloodstream, adding to the cholesterol-lowering benefit. In addition, the statins produce a modest elevation in HDL (“good”) cholesterol, and the two newest and most potent statins, atorvastatin (Lipitor) and rosuvastatin (Crestor), also lower blood triglyceride levels.

While the statins’ effects on blood lipid levels get (and deserve) most of the attention, followed by their effect on other aspects of heart disease prevention, these powerful medications have many other actions in the body.

Statins and cancer

When the statins were first introduced in the 1980s, some scientists worried that they might protect the heart at the cost of an increased risk of cancer. But those fears have proven groundless. In fact, a large series of trials agreed that statins do not increase the risk of cancer.

With these concerns aside, the pendulum began to swing in the opposite direction, as scientists began to ask if statins might actually reduce the risk of cancer. In general, scientists agree that statins are able to slow the growth of cells from human cases of prostate cancer, bladder cancer, breast cancer, and other malignancies.

These lab experiments are interesting, even hopeful. Still, it’s a long way from the lab to the clinic. What have we learned about the effects of statin drugs on human cancer?

One way to answer the question is to see if people taking statins have a lower (or higher) risk of developing cancer than otherwise similar people who are not taking these drugs. The major clinical trials of statins all focused on heart disease, but they reported no overall effects on the incidence of malignancy. When researchers have re-evaluated these data to concentrate on cancer, they have reported mixed results. Studies from Canada, Denmark, and the U.S. have found that statin users enjoy a 14% to 28% lower risk of cancer than nonusers, but other studies find no overall reduction in the risk of cancer.

Cancer is not one disease, but many. When scientists have honed in on how statins affect the risk of individual malignancies, they have also produced mixed results for colon cancer, lung cancer, and breast cancer.

Based on these results, most experts agree that there is no conclusive evidence that statins protect against cancer in humans. Still, the hints of benefit are strong enough to warrant additional research. And when the research has turned to prostate cancer, recent research has suggested statins may be beneficial.

Statins and prostate cancer

Studies of statins and prostate cancer got off to a disappointing start with a 2002 study that found no benefit for statin use in a case-control study. A 2007 study was even more discouraging, reporting that 3,302 men who took a statin had a slightly higher risk of prostate cancer over 15 years than 3,293 men who took a placebo. And a 2008 study of 1,943 men from Washington State found no link between statin use and prostate cancer.

In contrast to these discouraging reports, other studies are much more optimistic. A 2007 Finnish study of 49,446 men reported that statin users enjoyed a 25% lower risk of advanced prostate cancer when compared with men who took other cholesterol-lowering drugs or no cholesterol medication. The benefit grew with increasing duration of statin use. And a 2008 American study of 62,842 male veterans linked statin use with a 10% reduction in the risk of prostate cancer.

Statins for the prostate?

No — or, at least, not yet.

Much more research is needed before statin therapy can be recommended to reduce the risk of prostate cancer or any other noncardiovascular disease. Still, men who need a statin for their hearts may be pleased to learn that prostate protection is a possible “side effect” of statin therapy.

June 2009 update