Men who use cholesterol-lowering drugs known as statins may be cutting their risk for advanced prostate cancer in half, according to researchers who examined 10 years of data from the large, highly respected Health Professionals Follow Up Study.

However, use of statins -- a class of drugs that include such brands as Lipitor, Mevacor, and Zocor -- did not appear to change the risk for early, curable prostate cancer that had not spread beyond the prostate itself. Lead researcher Elizabeth Platz, ScD, presented the findings at the 2005 meeting of the American Association for Cancer Research -- and she included a caution.

"We believe it's very promising, but this is an observational study," said Platz, of the Johns Hopkins Bloomberg School of Public Health, in a press briefing. "We believe that more studies need to be done."

Len Lichtenfeld, MD, deputy chief medical officer for the American Cancer Society, agreed.

"This is not enough information to recommend that people begin taking statins [to lower their cancer risk]," said Lichtenfeld. "All drugs do have some side effects."

For the study, researchers looked at 34,438 men, ages 44-79, who were free of prostate cancer in 1990.

Every 2 years the men completed surveys about their health, including their use of cholesterol-lowering drugs. In 2000, about 90% of the men who reported being treated for high cholesterol said they were taking statins. Platz did not provide details about how many men this included.

That same year, 2,074 men from the entire study group reported having prostate cancer, and each diagnosis was confirmed by researchers.

When scientists compared the men who did and did not use cholesterol-lowering statins, they found that men who took the medication had:

• no difference in the risk of early, curable prostate cancer
• one half the risk of developing advanced prostate cancer
• one third the risk for fatal or metastatic (widespread) disease

Furthermore, the longer statins were used, the more the risk for advanced prostate cancer was found to drop.

"There is a real relationship here; it's not just a chance observance, because the longer people used cholesterol-lowering drugs, the lower the risk for advanced prostate cancer," said Lichtenfeld. "The study suggests that statins may play a role in [slowing] the progression of prostate cancer."

Did simply having lower blood cholesterol levels protect men from advanced prostate cancer? Or could the statin drugs have additional properties that interfere with the disease? Platz and her colleagues are doing further research to answer the first question.

The cholesterol that can clog arteries is also abundant in prostate cancer cells, according to Platz.

The second question requires further basic-science research, according to Platz.

Some lab studies have already found that statin drugs help to properly dispose of damaged cells, such as cancer cells, through a normal process called apoptosis, or programmed cell death. Cancer develops when abnormal cells in a part of the body begin to grow out of control.

Platz noted that statins also show anti-inflammatory activity in laboratory studies. Chronic inflammation has been linked to stomach, liver, and cervical cancers. (More information about infections, inflammation, and cancer is available in a special section of the Society's Cancer Facts & Figures 2005 called "Cancers Linked to Infectious Diseases.")

Platz's presentation about statins and prostate cancer was an informal, "early view" report for the AACR meeting. More details will be available when the findings are published in a medical journal.