PROSTATE-SPECIFIC ANTIGEN AS A PRETHERAPY PROGNOSTIC FACTOR IN PATIENTS TREATED WITH RADIATION-THERAPY FOR CLINICALLY LOCALIZED PROSTATE-CANCER

Purpose: This study was conducted to determine the value of prostate- specific antigen (PSA) as a pretherapy prognostic factor for localized prostate cancer treated with primary irradiation (RT). Patients and Methods: Between March 1987 and December 1990, 254 patients with pretherapy PSA determinations were treated for clinical stage A2 to C prostate adenocarcinoma. In conjunction with other prognostic factors, pretherapy PSA was evaluated to determine whether it had independent predictive value for disease outcome. Results: Pretherapy PSA was highly and directly correlated with clinical stage, tumor grade, and acid phosphatase level. With a median follow-up duration of 24 months, 241 patients (95%) were fully assessable for disease outcome. In these patients, PSA and tumor grade were the sole independent predictive factors for tumor relapse (ie, clinically determined and/or increasing PSA level). The combination of pretherapy PSA and tumor grade information defined groups of patients with distinctly different outcome. For patients in low- (favorable PSA and tumor grade), intermediate- (favorable PSA or tumor grade), and high- (adverse PSA and tumor grade) risk categories, the actuarial rates of survival free of tumor relapse or increasing PSA level were 94%, 77%, and 42% at 3 years, respectively (P < .0001). Conclusion: Pretherapy PSA is a strongly independent prognostic factor for disease outcome following primary RT. The combination of adverse pretherapy PSA and unfavorable tumor grade identified a cohort of patients with a high risk of early treatment failure in whom combined modality therapy may be appropriately investigated.