PSA Test for Prostate Cancer May Be Affected by Statin Use

A new study shows that men who take cholesterol-lowering medications called statins have lower blood levels of prostate-specific antigen (PSA), a biomarker for prostate cancer risk.

That drop in PSA level does not necessarily mean the medications protect against disease, researchers say in the Journal of the National Cancer Institute.

But discussion continues about the possibility that statins offer some protection against the disease.

Report author Dr. Robert Hamilton, at the University of Toronto, says, "The reduction in PSA was in proportion to the dose of statins that were taken and to the reduction of cholesterol levels."

Dr. Hamilton says this may be an indicator of a possible protective effect.

Higher Statin Level, Higher the Drop

The study was conducted because of "encouraging recent data" from four previous studies showing an association between statin therapy and reduced PSA levels, and a reduced risk of advanced prostate cancer, he says.

The study followed 1,214 men who were prescribed statins between 1990 and 2006 at the Durham Veterans Affairs Medical Center in North Carolina.

PSA levels declined by about 4 percent after statin therapy was started, with the greatest reductions seen in men who took the largest doses of statins and had the largest drops in blood cholesterol levels.

The results parallel those of a study reported in 2005 by a group led by Dr. Dov Kadmon, at the Baylor College of Medicine.

"Our study was the first to show a relationship between PSA levels and either lowering of cholesterol or treatment with statins," says Dr. Kadmon. "We could not distinguish whether lowering cholesterol or statin treatment was responsible, because our study was not designed to show that."

Dr. Kadmon and his colleagues followed 100 commercial airline pilots, a group chosen because federal regulations require them to have regular medical exams.

The five-year study showed that "pilots on statins had a 46 percent decrease in PSA levels, while the control group had a slow increase in PSA levels, which are known to go up with age," he says.

Anti-Inflammatory Action Examined

The study was too small and too short to tell whether statins might protect against prostate cancer, says Dr. Kadmon.

"But we know that when men have higher PSA levels, there is a higher chance that they will be diagnosed with prostate cancer," he notes. "It is worth looking into by conducting a larger study."

"There is no question that a large, randomized, controlled trial with a long follow-up would most likely answer the question," says Dr. Hamilton. "It would be an expensive, huge undertaking."

Why statins affect PSA levels is unclear.

"We have some idea of how statins interact with prostate biology,” he says. “But we don't know the exact mechanism by which statins influence PSA."

The anti-inflammatory action of statins is one of the possible mechanisms.

"We need to learn more about prostate cancer and statins before we launch a huge study," he adds.

Always consult your physician for more information.