EFFECT OF FINASTERIDE ON PROSTATE-SPECIFIC ANTIGEN DENSITY

Objective. Prostate-specific antigen density (PSAD) has been proposed as a diagnostic marker for prostate cancer. Because treatment with fin asteride may affect PSAD differently in men with BPH compared with men with BPH plus prostate cancer, we evaluated the diagnostic utility of PSAD in men treated with finasteride for twelve months. Methods. Data for this analysis were obtained from 895 men with BPH enrolled in a t welve-month placebo-controlled North American study. Prostate volume w as measured by magnetic resonance imaging and PSA was measured by the Hybritech immunoradiometric assay. Results. Treatment with finasteride for twelve months increased the positive predictive value of PSAD for identifying the presence of prostate cancer from 14 percent to 30 per cent. Using PSA values alone with a cutoff of 10 ng/mL at baseline and 5 ng/mL after twelve months of treatment, similar specificity and sen sitivity could be achieved. Conclusion. The data suggest that adjustme nt of PSA values during treatment with finasteride can be used to main tain the diagnostic accuracy for prostate cancer while PSAD can be use d to provide additional reassurance without requiring adjustment for t reatment.