Hair-Loss Drug Impedes Prostate Cancer Detection in Middle-Aged Men

Researchers at Brigham and Women's Hospital (BWH) have found that the prostate specific antigen (PSA) cancer screening test is falsely lowered by a factor of two in middle-aged men who have taken Propecia, a hair-loss drug used by more than four million men worldwide, for one year. These findings are published on December 5, 2006 in the 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 Anthony D'Amico, MD, PhD, chief, Genitourinary Radiation Oncology at the Dana-Farber/Brigham and Women's Cancer Center and lead author of the study. "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 one year have been used to recommend a prostate biopsy," said D'Amico, who is also a professor of Radiation Oncology at Harvard Medical School (HMS).

PSA is a protein produced by the prostate gland and is often elevated in the presence of prostate cancer and other prostate disorders. A blood test to measure PSA is the most effective test available for the early detection of prostate cancer and levels are reported as nanograms of PSA per milliliter of blood (ng/ml). Controversy exists as to what is considered a normal or abnormal PSA level, however, a high PSA level and the rise in PSA levels over time, may be indicative that cancer is present and a biopsy is necessary.

In this study, researchers aimed to determine whether 1 mg/day of finasteride (Propecia), has similar effects on PSA levels as that of 5 mg/day doses of finasteride (Proscar), which have been proven in previous studies to significantly decrease PSA levels, and is used in the treatment for symptoms of an enlarged prostate. The researchers studied 355 men aged 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.

Researchers found that for men who received 1mg/day of finasteride in an analogous fashion to Proscar, PSA levels dropped by a factor of two in one year. As a result of this decrease, researchers recommend that men between 40 and 60 years of age who take Propecia for hair loss have their PSA levels adjusted by a factor of 2 just as they would if they were taking Proscar.

This research was funded by Merk & Co., Inc.