Serum Markers as a Predictor of Response Duration and Patient Survival After Hormonal Therapy for Metastatic Carcinoma of the Prostate

Abstract

PURPOSE: Prostate specific antigen (PSA), prostatic acid phosphatase and alkaline phosphatase were analyzed in 2 large prospective multicenter and multinational trials to assess their correlation with time to progression and overall survival after hormonal therapy for metastatic carcinoma of the prostate. MATERIALS AND METHODS: A total of 868 patients who underwent medical or surgical castration was randomized to receive an oral antiandrogen (nilutamide) or placebo. The serum markers under study were measured at baseline and at 1, 3, 6 and every 6 months thereafter. RESULTS: At baseline the strongest predictive factor was serum alkaline phosphatase. Patients with an alkaline phosphatase of 2 or less times normal lived almost twice as long as those with a level of more than 2 times normal (p < 0.0001). The longer survival was observed in patients whose PSA became normal 3 months after initiation of hormonal therapy compared to those whose PSA never reached normal (p < 0.0001). CONCLUSIONS: Serum markers at baseline and during the few months after initiation of hormonal therapy can provide prognostic information for the clinical treatment of patients with metastatic carcinoma of the prostate. In addition, the PSA level at month 3 can serve as a surrogate end point in clinical trials.