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

Objective To investigate any differences in changes in serum prostate speci fic antigen (PSA) levels in patients with benign and malignant prostatic di sease in response to the testosterone surge after administering a luteinizi ng hormone-releasing hormone (LHRH) analogue. Patients and methods The study included 54 patients referred to the urology clinic with intermediate PSA levels (4-10 ng/mL) or an abnormal digital re ctal examination. Forty-five patients received a single injection of LHRH a nalogue 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 correlate d with the biopsy results. The PSA changes were compared with basal PSA lev els and the free/total PSR ratio (f/tPSA). Results Of the 45 patients who underwent: prostate biopsy, histopathology s howed prostate cancer in 11, benign prostatic hyperplasia in 33 and prostat ic intraepithelial neoplasia in one. Patients with cancer had a significant ly greater increase in serum PSA levels during the first week, after LHRH i njection than those in the benign and control groups. Receiver operating ch aracteristic curves showed that the percentage change in PSA level on day 5 was more diagnostic than total PSA and f/tPSA. Conclusions There was a marked difference in the PSA response of patients w ith benign or malignant disease to the testosterone surge produced by the L HRH analogue. Although a larger study would be needed before LHRH-induced p rovocation could be proposed as a clinical test, in this small series the r esponse was better than that for total PSA or f/tPSA in differentiating ben ign and malignant disease.