Pretreatment PSA velocity as a predictor of disease outcome following radical radiation therapy.

Abstract

Pretreatment prostate-specific antigen velocity (PSAV) greater than 2.0 ng/mL/year has been identified as a predictor of disease-specific survival (DSS) and overall survival (OS) after radiotherapy for prostate adenocarcinoma. This study aimed to independently verify if pretreatment PSAV is associated with biochemical disease-free survival (bDFS), DSS, or OS in men undergoing radiation therapy. A total of 473 patients treated with radiation therapy for localized prostate cancer formed the study cohort. No men received neoadjuvant or adjuvant hormones. Kaplan-Meier and Cox regression analysis were used to evaluate if PSAV predicted disease endpoints. Men with a PSAV greater than 2.0 ng/mL/year had a shorter bDFS compared with men with a PSAV of 2.0 ng/mL/year or less (median, bDFS 68 months vs. 97 months; p = 0.0003). However, on multivariate analysis, PSAV was no longer a significant predictor of bDFS in the entire cohort (p = 0.09). PSAV did not predict DSS or OS (p = 0.55 and p = 0.99, respectively). In patients with high-risk disease, PSAV predicted bDFS on univariate (p = 0.0002) and multivariate (p = 0.02) analysis, but not DSS or OS. Pretreatment PSAV greater than 2.0 ng/mL/year is associated with reduced bDFS. However, PSAV is an independent predictor of bDFS only in high-risk patients. PSAV does not predict survival outcomes.