Pretreatment PSA Velocity and Risk of Death From Prostate Cancer Following External Beam Radiation Therapy

Abstract

Men with localized prostate cancer and a preoperative prostate-specific antigen (PSA) velocity greater than 2.0 ng/mL per year experience a 10-fold increase in prostate cancer-specific mortality despite surgery. To assess whether a greater than 2.0-ng/mL increase in PSA level during the year prior to diagnosis was significantly associated with prostate cancer-specific mortality following radiation therapy (RT). Between January 1, 1989, and December 1, 2002, 358 men treated with RT for localized prostate cancer formed the study cohort (median age at treatment, 71.2 [range, 43.2-83.5] years). A Cox regression multivariable analysis was used to evaluate whether a PSA velocity greater than 2.0 ng/mL per year was significantly associated with prostate cancer-specific mortality and all-cause mortality after controlling for prognostic factors available at diagnosis. Time to prostate cancer-specific mortality for the 125 men with low-risk prostate cancer (clinical tumor category T1c or T2a and PSA level <10.0 ng/mL and Gleason score < or =6) and the 233 men with higher-risk disease, stratified by the PSA velocity. A PSA velocity greater than 2.0 ng/mL per year was significantly associated with a shorter time to prostate cancer-specific mortality (adjusted hazard ratio [HR], 12.0; 95% confidence interval [CI], 3.0-54.0; P = .001) and all-cause mortality (adjusted HR, 2.1; 95% CI, 1.3-3.6; P = .005) when compared with men whose PSA velocity was 2.0 ng/mL per year or less. Men presenting with low-risk disease and a PSA velocity greater than 2.0 ng/mL per year had a 7-year estimate of prostate cancer-specific mortality of 19% (95% CI, 2%-39%) compared with 0% for men whose PSA velocity was 2.0 ng/mL per year or less. The corresponding values for men with higher-risk disease were 24% (95% CI, 12%-37%) and 4% (95% CI, 0%-11%), respectively. A greater than 2.0-ng/mL increase in PSA level during the year prior to diagnosis is associated with a significantly higher risk of death due to prostate cancer following RT despite having low-risk disease. Such men who are planning to undergo RT and are in good health could be considered for RT combined with androgen suppression therapy because this approach improves survival in men with higher-risk disease.