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

Abstract

Background and purpose: 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.

Materials and methods: 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).

Results: 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).

Conclusion: Early PSA failure following radiation is a poor prognostic factor, as it is associated with increased DM, PCSM, and overall mortality.

Keywords: Brachytherapy; Cause-specific survival; Distant metastases; Overall survival; PSA failure; Prostate cancer.