Change in Prostate Specific Antigen Concentration in Men with Prostate Specific Antigen Less than 2.5 ng/ml Taking Low Dose Finasteride or Dutasteride for Male Androgenetic Alopecia.

PURPOSE: In this retrospective cohort study we assessed the effect on prostate specific antigen concentration of low dose finasteride or dutasteride treatment for male androgenetic alopecia in men with baseline serum prostate specific antigen less than 2.5 ng/ml. MATERIALS AND METHODS: The cohort consisted of 1,379 consecutive male patients who were treated for androgenetic alopecia with finasteride 1.25 mg daily or dutasteride 0.5 mg every 3 days in 2002 to 2012 and who underwent prostate specific antigen measurements at baseline and at least once thereafter. Patients in whom baseline or followup prostate specific antigen after prescription exceeded 2.5 ng/ml were excluded from study to rule out men with a higher likelihood of prostate cancer. Patients were stratified according to age, baseline prostate specific antigen, medication type and treatment duration. RESULTS: Overall low dose 5α-reductase inhibitor treatment reduced prostate specific antigen by 27.8% relative to baseline. Of the patients 1,094 (79.3%) showed prostate specific antigen decreases (average 40.8%). In the remaining 285 patients (20.7%) prostate specific antigen was stable or increased (average 24.2% increase). Closer analysis largely showed that only men with baseline prostate specific antigen 0.5 ng/ml or greater had a treatment related prostate specific antigen reduction. On multivariate logistic analysis low baseline prostate specific antigen was significantly associated with stable/increased prostate specific antigen. Low dose dutasteride and finasteride reduced prostate specific antigen to similar degrees (31.1% and 25.1%, respectively). A marked prostate specific antigen decrease of 26.0% was observed even after short-term treatment (3 to 6 months). CONCLUSIONS: Dutasteride and finasteride reduced prostate specific antigen to similar degrees. This effect was observed soon after commencing treatment. In patients with low baseline prostate specific antigen the levels could remain stable or even increase. These findings are limited to men with baseline prostate specific antigen less than 2.5 ng/ml.