SERUM MARKERS AS A PREDICTOR OF RESPONSE DURATION AND PATIENT SURVIVAL AFTER HORMONAL-THERAPY FOR METASTATIC CARCINOMA OF THE PROSTATE

Purpose: Prostate specific antigen (PSA), prostatic acid phosphatase a nd alkaline phosphatase were analyzed in 2 large prospective multicent er and multinational trials to assess their correlation with time to p rogression and overall survival after hormonal therapy for metastatic carcinoma of the prostate. Materials and Methods: A total of 868 patie nts who underwent medical or surgical castration was randomized to rec eive an oral antiandrogen (nilutamide) or placebo. The serum markers u nder 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 obs erved 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 m onths after initiation of hormonal therapy can provide prognostic info rmation for the clinical treatment of patients with metastatic carcino ma of the prostate. In addition, the PSA level at month 3 can serve as a surrogate end point in clinical trials.