A prospective dose escalation trial of high-dose-rate brachytherapy boost for prostate cancer: Evidence of hypofractionation efficacy?

Abstract

Purpose: The study aimed to evaluate mature outcomes of a Phase I/II high-dose-rate brachytherapy (HDRB) boost protocol. Methods and materials: We analyzed data from 88 patients with T1a-T3a, N0, M0 prostate adenocarcinoma treated on a prospective Phase I/II HDRB boost protocol of 16 (n = 47) or 20 Gy (n = 41) in four fractions, without planned androgen deprivation therapy. HDRB was added to 46 Gy of external beam radiotherapy (EBRT). Outcomes were compared to a contemporaneous retrospective cohort of 104 patients receiving 66 Gy EBRT monotherapy. The primary endpoint was freedom from biochemical failure, defined as a 2 ng/mL rise above the lowest prostate-specific antigen (PSA) (FFbFn2), wh..