Differential response of prostate specific antigen to testosterone surge after luteinizing hormone-releasing hormone analogue in prostate cancer and benign prostatic hyperplasia.

Abstract

To investigate any differences in changes in serum prostate specific antigen (PSA) levels in patients with benign and malignant prostatic disease in response to the testosterone surge after administering a luteinizing hormone-releasing hormone (LHRH) analogue. The study included 54 patients referred to the urology clinic with intermediate PSA levels (4-10 ng/mL) or an abnormal digital rectal examination. Forty-five patients received a single injection of LHRH analogue depot each at one week before prostate biopsy and nine served as a control group. Changes in PSA levels in response to the testosterone surge from the LHRH analogue were recorded after 5 and 7 days, and were correlated with the biopsy results. The PSA changes were compared with basal PSA levels and the free/total PSA ratio(f/tPSA). Of the 45 patients who underwent prostate biopsy, histopathology showed prostate cancer in 11, benign prostatic hyperplasia in 33 and prostatic intraepithelial neoplasia in one. Patients with cancer had a significantly greater increase in serum PSA levels during the first week after LHRH injection than those in the benign and control groups. Receiver operating characteristic curves showed that the percentage change in PSA level on day 5 was more diagnostic than total PSA and f/tPSA. There was a marked difference in the PSA response of patients with benign or malignant disease to the testosterone surge produced by the LHRH analogue. Although a larger study would be needed before LHRH-induced provocation could be proposed as a clinical test, in this small series the response was better than that for total PSA or f/tPSA in differentiating benign and malignant disease.