Objectives: To evaluate, in a prospective study, the diagnostic accuracy of PSA in patients with a prior negative prostate biopsy who were given finasteride for 6 months.
Materials and methods: 91 men with prior negative biopsy findings, including HGPIN and excluding ASAP, were instructed to take finasteride for 6 months. All patients were evaluated at study onset and after 6 months by clinical examination, digital rectal examination (DRE), International Prostate Symptom Score (IPSS) and National Institutes of Health Chronic Prostatitis Symptom Index (NHI-CPSI). Prostate biopsy was repeated at 6 months. PSA levels were measured at baseline and after 1, 3 and 6 months. We calculated the receiver operating characteristics (ROC) curve of PSA under the effect of finasteride for detecting prostate cancer.
Results: The median PSA level decreased similarly both in those with prostate cancer and in those without findings of cancer. There was no statistically significant difference between the two groups. The areas under the ROC curve (AUC) of PSA at study onset and after 6 months of therapy with finasteride were, respectively, 0.48 (95% CI 0.36-0.61) and 0.54 (95% CI 0.42-0.66). There was no statistically significant difference between the two areas.
Conclusions: The results of our study show that PSA itself has a low diagnostic accuracy for detecting prostate cancer in men with prior negative prostate biopsy findings. Finasteride does not seem to improve the accuracy of PSA in this particular population of patients.