Background: Pretreatment serum prostate specific antigen (PSA) level is a powerful prognostic factor for clinically localized prostate carcinoma. The traditional prognostic factors, T classification and Gleason score, appear to have been relegated to a minor position. This study was conducted to evaluate the relative prognostic roles of PSA, T classification, and Gleason score in a large cohort of men irradiated in the PSA era.
Methods: The authors analyzed the outcome for a group of 938 men with T1-T4, N0 or NX, M0 prostate carcinoma who received definitive external beam radiation therapy as their only initial treatment during the period 1987-1995. The T classifications were as follows: T1, 283 (30%); T2, 360 (38%); T3/T4, 295 (31%). Gleason scores were as follows: Gleason 2-6, 580 (62%); Gleason 7, 224 (24%); Gleason 8-10, 122 (13%). Pretreatment PSA levels (ng/mL) were as follows: PSA < or = 4, 167 (18%); PSA 4 to < or = 10, 363 (39%); PSA 10 to < or = 20, 259 (28%); PSA > 20, 149 (16%). At a mean follow-up of 43 months (range, 6-106 months), disease outcome specified as relapse/rising PSA, local recurrence, or metastasis was analyzed using univariate and multivariate techniques.
Results: The 6-year actuarial incidences of relapse/rising PSA, local recurrence, and metastases were 48%, 27%, and, 6%, respectively. In multivariate regression, pretreatment PSA level, T classification, and Gleason score were each independently highly significantly (P < 0.001) correlated with every endpoint. Pretreatment PSA level was the most significant variable for rising PSA and local recurrence, and T classification was the most significant variable for metastatic relapse. Using relapse/rising PSA as the endpoint, the authors formulated a highly significant 6-tier prognostic grouping based on PSA, T classification, and Gleason score, as follows: Category I: T1/T2, PSA < or = 4, and Gleason 2-6 (relapse rate, 6%); Category II: T1/T2, PSA < or = 4 and Gleason 7-10, or PSA 4 to < or = 10 and Gleason 2-7 (relapse rate, 30%); Category III: T1/T2, PSA 4 to < or = 10 and Gleason 8-10, or PSA 10 to < or = 20 and Gleason < 8 (relapse rate, 40%); Category IV: T3/T4, PSA < 10 (relapse rate, 46%); Category V: T3/T4, PSA 10 to < or = 20, and Gleason < 8 (relapse rate, 57%); Category unfavorable: any T, PSA > 20 and any Gleason, or PSA 10 to < or = 20 and Gleason 8-10 (relapse rate, 88%).
Conclusions: The establishment of T classification and Gleason score as independent prognostic factors bridges an apparent gap between an older era and the current PSA era. PSA has supplemented, rather than supplanted, the utility of the traditionally established prognostic factors for clinically localized prostate carcinoma.