Radical radiotherapy in high-risk prostate cancer patients with high or ultra-high initial PSA levels: a single institution analysis

Abstract

Purpose of this study is to analyze outcomes and pre-treatment prognostic factors in high-risk prostate cancer patients with initial PSA ≥ 20 ng/mL, treated with high-dose external beam radiotherapy (EBRT) and androgen deprivation therapy (ADT) in a single institution. Between March 2003 and December 2011, 155 consecutive high-risk prostate cancer patients (a) presenting with pre-treatment PSA level ≥ 20 ng/mL, (b) treated with definitive EBRT, and (c) with a minimum follow-up of 24 months were included in this retrospective analysis. Phoenix definition was used to define biochemical control. Primary endpoints were as follows: biochemical disease-free survival (bDFS), distant metastasis-free survival (DMFS), cancer-specific survival (CSS) and overall survival (OS). Multivariate analysis was performed to determine the independent prognostic impact of pre-treatment clinical factors [T stage, PSA, and Gleason score (GS)]. At a median follow-up time of 62 months, actuarial bDFS, DMFS, CSS, and OS at 5 years were 64.8, 85.2, 95.8, and 94.4 %, respectively. On multivariate analysis, only GS was significantly associated with three clinical endpoints (bDFS: HR 1.6; p = 0.022, CSS: HR 4.27, p = 0.044, OS: HR 2.6; p = 0.038). Pre-treatment zenith PSA was associated only with bDFS (HR 1.87; p = 0.027). Patients with "high" PSA levels (≥ 20 ng/mL) showed favorable clinical outcomes, supporting the role of local radiotherapy as primary therapy in combination with long-term ADT in patients with high PSA levels at diagnosis. A GS of 8-10 is the strongest predictor of outcome.