Hair-loss version of finasteride may impede prostate cancer detection

PSA is falsely lowered by a factor of two in middle-aged men who have taken the hair-loss drug finasteride (Propecia) for 1 year, according to a study published in Lancet Oncology online.

“For these men, the PSA level needs to be corrected, or the detection of prostate cancer may not occur until it is more aggressive,” said lead author Anthony D’Amico, MD, PhD, of the Dana-Farber/Brigham and Women’s Cancer Center in Boston. “It is also important to note that, because PSA becomes a more accurate indicator for cancer presence when taking finasteride-containing drugs like Propecia, changes in PSA as low as 0.3 ng/mL in 1 year have been used to recommend a prostate biopsy.”

In the study, Dr. D'Amico and Claus Roehrborn, MD, of the University of Texas, Southwestern in Dallas, aimed to determine whether finasteride, 1 mg/day, had similar effects on PSA levels as that of finasteride (Proscar), 5 mg/day, which is indicated for the treatment of BPH. The researchers studied 355 men ages 40 to 60 years old for 48 weeks in a placebo-controlled, randomized, double-blind study. Participants’ PSA levels were obtained at the start of the study and once every 12 weeks for the duration of the study.

The team found that for men who received 1 mg/day of finasteride in an analogous fashion to Proscar, PSA levels dropped by a factor of two in 1 year. As a result of this decrease, researchers recommend that men between 40 and 60 years of age who take the 1-mg formulation of finasteride for hair loss have their PSA levels adjusted by a factor of two just as they would if they were taking the 5-mg formulation.