Prostatic Specific Antigen and the Prediction of Prognosis in Metastatic Prostatic Cancer

Serum prostate‐specific antigen (PSA) levels were studied in the EORTC trial of zoladex plus flutamide versus orchidectomy in metastatic prostatic cancer. Forty‐four of 60 patients had a decrease of PSA to ≤10 ng/ml at 3 to 6 months after treatment. The combination of a PSA > 10 ng/ml after 3 to 6 months treatment and less than 15 spots on the bone scintigram at entry gave the highest probability of not having progressed by 24 months. A rising PSA anticipated bone progression by 6 to 12 months in 13 of 28 patients (46%). The PSA at entry to the trial was related to survival; a discriminant of 300 ng/ml distinguished a poor and better risk group. The lowest level of PSA reached during the first 6 months of treatment was also a univariate survival factor.