High blood levels of PSA (prostate-specific antigen) can signal prostate cancer, although other benign conditions also raise PSA levels. Men with high and rising PSA levels are usually advised to undergo prostate biopsies.
Might statins' possible prostate cancer effects involve PSA? To find out, Duke University researchers studied changes in PSA levels in 1,214 men who took statins.
"On average, PSA declined by 4.1% after starting a statin," study researcher Robert J. Hamilton, MD, MPH, tells WebMD. "But what was really interesting was that the decline in PSA was proportional to the decline in cholesterol associated with the statin."
While the average PSA decline linked to statins was tiny, a bigger decrease was seen in men who started out with the highest PSA levels (2.5 ng/mL or more) -- but only among those who had the greatest decrease in cholesterol. These men had a 17.4% drop in PSA.
That could mean two different things, Hamilton suggests:
Statins may affect prostate biology.
Men taking statins may lower their PSA scores without lowering their risk of prostate cancer, making their PSA tests more difficult to interpret.
"Maybe these findings explain the reductions in advanced prostate cancer linked to statins," Hamilton says. "Or maybe we should worry about this decline in PSA. Could statins confuse the interpretation of PSA tests?"
Probably not, says Ian M. Thompson, MD, professor and chairman of the department of urology at the University of Texas Health Science Center at San Antonio. He says it's not clear how much those higher-than-average PSA scores would have gone down all by themselves -- the "regression to the mean" phenomenon often seen with clinical tests.
So if a man on statins chooses to undergo PSA screening and has a PSA test with a borderline score, Thompson would recommend simply repeating the test.