Men's Health: Hair Loss Drug Messes Up PSA Test
Losing their hair to middle age can feel traumatic, so many men take antibaldness drugs. But hair loss is nothing compared with the trauma of prostate cancer. And one might lead to the other in a disturbing scenario laid out in the current online version of the journal Lancet Oncology.
Propecia, a popular hair-loss drug, can skew results from the prostate-specific antigen (PSA) test used to screen men for cancer, researchers report. "It can reduce the values by 50 percent," says Claus Roehrborn, a urologic oncologist at the University of Texas Southwestern Medical Center in Dallas and an author of the report. "So a man in his 50s, taking this lifestyle drug, might get a result of 2, when it's really a 4, which is more alarming." The higher number could indicate a growing cancer.
The drug might also prompt unnecessary biopsies in men who don't have a high cancer risk, says Martin Resnick, chair of urology at Case Medical Center in Cleveland. Many urologists now look for a rapid increase from one PSA test to the next, rather than an absolute number on one test, as a sign of potential danger. But, Resnick points out, if a Propecia patient has one test with artificially suppressed values, stops taking the baldness drug, and then has another test, any increase could look huge. And that would send men to the surgeon for biopsies that they don't really need.
Merck, Propecia's maker, does note in its patient information that the drug shrinks PSA values, but this is the first published work showing the surprising size of the effect. (The company funded this research.) The finding should be a red flag for physicians as well as patients, Resnick says. The prudent thing to do for men on Propecia, according to Resnick and Roehrborn, is to double their PSA values.
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