The magnitude of change in serum prostate specific antigen (PSA) after 5-alpha reductase inhibitor therapy may help diagnose prostate cancer (PCa) in men with persistently increased serum PSA and previously negative biopsies, according to a study.
Steven A. Kaplan, MD, of Cornell University in New York, and colleagues examined the effect of 5-alpha reductase inhibitor therapy on PCa detection in 276 men with PSA greater than 4 ng/mL (208 subjects) or a PSA velocity change of 0.75 ng/mL (68 subjects) and a normal digital rectal examination who had previously undergone biopsy at least twice. Patients were given finasteride (154) or dutasteride (122) daily. In phase 1, PSA was measured at six and 12 months in 97. In phase 2, biopsy was performed on patients with a nadir PSA of more than 0.4 ng/mL.
In phase 1 at one year, PSA levels had decreased by 46.7% and prostate volume had decreased by 17.9%, the researchers reported in The Journal of Urology (2012;188:757-761) In 27.8% of the 97 patients, PCa was detected with a mean minimum PSA velocity of 0.6 ng/mL from a nadir of 0.4 ng/mL. At a mean of 14.6 months, 26.8% of the 179 participants in phase 2 underwent repeat biopsy. Of these, 54.1% had PCa, and Gleason score 7 or greater disease was detected in 76.9% of them.
“The data in this study support the concept that the magnitude of change in serum PSA after one year of 5α-reductase inhibitor therapy may be useful in diagnosing prostate cancer in men with persistently increased serum PSA and previously negative prostate biopsies,” the authors write.