Association of early PSA failure time with increased distant metastasis and decreased survival in prostate brachytherapy patients.

Abstract

We investigated whether earlier PSA failure following prostate brachytherapy is associated with increased rates of distant metastases (DM), prostate cancer-specific mortality (PCSM), and overall mortality. We retrospectively analyzed 2818 patients who underwent brachytherapy ± external beam radiation therapy (EBRT) ± androgen deprivation therapy (ADT). With median follow-up of 5.52 years, 264 patients experienced PSA failure at a median time of 3.25 years. Patients were stratified to early vs. late PSA failures at cutoffs of 1.5 years, 3 years, or 5 years, and tested in univariate/multivariate analyses for freedom from DM, cause-specific survival (CSS), and overall survival (OS). Among patients with PSA failures, 69 (26%) patients experienced DM, 47 (18%) PCSM, and 56 (21%) deaths from other causes. Patients with rapid PSA failures demonstrated increased rates of DM, PCSM, and overall mortality, despite higher total BED and longer ADT. In multivariate analysis with a PSA failure interval <3 years, the hazard ratio (HR) for DM was 3.92 (95% CI: 2.34-6.55; p=0.000); HR for PCSM was 2.79 (95% CI: 1.45-5.38; p=0.002); and HR for overall mortality was 2.28 (95% CI: 1.50-3.48; p=0.000). Early PSA failure following radiation is a poor prognostic factor, as it is associated with increased DM, PCSM, and overall mortality.