Predicting recurrence after radical prostatectomy for patients with high risk prostate cancer

Previous studies have shown that patients with clinical stage T2c-T3 prostate cancer, serum prostate specific antigen (PSA) at diagnosis greater than 20 ng./ml. or a biopsy Gleason score of 8 to 10 are at high risk for disease recurrence after radical prostatectomy. We determined the most important pretreatment predictors of disease recurrence in this high risk population.

We identified 547 patients with high risk prostate cancer who underwent radical prostatectomy at University of California, San Francisco or as part of the Cancer of the Prostate Strategic Urological Research Endeavor data base, a longitudinal disease registry of patients with prostate cancer. High risk disease was defined as 1992 American Joint Committee on Cancer clinical stage T2c-T3 disease in 411 patients, serum PSA at diagnosis greater than 20 ng./ml. in 124 and/or biopsy Gleason score 8 to 10 in 114. Disease recurrence was defined as PSA 0.2 ng./ml. or greater on 2 consecutive occasions after radical prostatectomy or second cancer treatment more than 6 months after surgery. The Cox proportional hazards analysis was performed to determine significant independent predictors of disease recurrence. The likelihood of disease recurrence for clinically relevant patient groups was determined using the Kaplan-Meier method and compared using the log rank test.

Median followup after surgery was 3.1 years. Disease recurred in 177 patients (32%). Multivariate analysis demonstrated that serum PSA at diagnosis, biopsy Gleason score, ethnicity and the percent of positive prostate biopsies were significant independent predictors of disease recurrence, while patient age and clinical tumor stage were not. Patients with a Gleason score 8 to 10 tumor and a serum PSA of 10 ng./ml. or less had a significantly higher likelihood of remaining disease-free 5 years after surgery than those with PSA greater than 10 ng./ml. (47% versus 19%, p <0.05). Patients with a serum PSA at diagnosis of greater than 20 ng./ml. and a Gleason score of less than 8 had a significantly higher likelihood of remaining disease-free 5 years after surgery than similar patients with a Gleason score of 8 or greater (45% versus 0%, p <0.05).

PSA, Gleason score, ethnicity and the percent of positive prostate biopsies appear to be the most important pretreatment predictors of disease recurrence in men with high risk prostate cancer. Patients with high grade disease may continue to be appropriate candidates for local therapy if PSA is less than 10 ng./ml. at diagnosis or there are fewer than 66% positive prostate biopsies.