SAN FRANCISCO—Prostate biopsies performed after treatment with 5-alpha reductase inhibitors increase the rate of prostate cancer detection, researchers reported at the American Urological Association annual meeting.
Steven Kaplan, MD, and colleagues at Weill Cornell Medical College in New York, based that conclusion on findings from a study of 276 men with a prior negative prostate biopsy performed because of an elevated PSA level or a change in PSA level of 0.75 ng/mL or greater. The men had been started on treatment with a 5-alpha reductase inhibitor, either finasteride 5 mg or dutasteride 0.5 mg.
The study consisted of two phases. In phase 1, which included 97 patients, investigators measured PSA levels at six and 12 months; all subjects underwent a repeat transrectal, ultrasound-guided, 12-core biopsy at one year. The objective was to determine a PSA velocity from nadir for subsequent testing. Of the 97 men, 27 (27.8%) had prostate cancer on repeat biopsy. All had a minimum PSA velocity change from nadir of 0.4 ng/mL or greater.
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In phase 2, which included 179 men, the researchers used a change in PSA level of 0.4 ng/mL or greater from nadir to trigger a repeat biopsy. Forty-eight men (26.8%) met this criterion and underwent a repeat biopsy a mean of 14.6 months after starting therapy with a 5-alpha reductase inhibitor. In these men, the mean PSA and prostate volume declined by 2.1 ng/mL (42.3%) and 5.6 cc (16.3%). Of the 48 patients, repeat biopsy revealed prostate cancer in 26 (54.1%); 20 of these patients had Gleason scores of 7 or higher.
The authors noted that their findings suggest that a PSA velocity change of 0.4 ng/mL from nadir after a minimum of six months of 5-alpha reductase inhibitor therapy “markedly enhances the detection rate of prostate cancer in men with prior negative biopsy.” They concluded that the “potential role of these agents to enhance prostate cancer detection rates should be analyzed in larger prospective clinical trials.”
