Adjuvant radiotherapy in prostate cancer: predictors of prostate-specific antigen recurrence from the CaPSURE database.

Objectives: To analyze an observational database of prostate cancer, assessing for patterns of use and predictors of prostate-specific antigen (PSA) recurrence after adjuvant radiotherapy (RT).
Methods: From the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE), 5336 men underwent prostatectomy from 1989 to 2004. Of these 5336 men, 96 men (1.8%) underwent adjuvant RT. These 96 men were classified as having low (Stage T1c-T2a and PSA level of 10 ng/mL or less and Gleason score of 6 or less), intermediate (Stage T2b or PSA level greater than 10 ng/mL and 20 ng/mL or less or Gleason score 7), or high (Stage T2c or higher or PSA level greater 20 ng/mL or Gleason score of 8 or greater) risk of PSA recurrence. PSA recurrence was defined as two consecutive PSA levels greater than 0.2 ng/mL. Differences between patients who experienced failure were assessed by chi-square tests or analysis of variance. Univariate and multivariate analyses were performed using a Cox proportional hazard regression model.
Results: Of the 96 men, 27 (28%) experienced PSA failure and 20 (21%) received additional treatment, with a median of 60 months of follow-up. The clinical risk group (P <0.01), PSA level at diagnosis (P <0.01), Gleason score (P <0.01), and seminal vesicle invasion (P <0.01) all significantly associated with PSA recurrence. The clinical risk group was the sole predictor of PSA recurrence-free survival on multivariate analysis (hazard ratio 2.4, 95% confidence interval 1.7 to 8.3, P = 0.007).
Conclusions: Adjuvant RT was not frequently used in men enrolled in CaPSURE. PSA recurrence was observed more frequently in men with high-risk disease, suggesting that adjuvant RT is not adequate therapy and that these men might benefit from the combined use of hormonal therapy and RT.