Treatment outcomes of prostate cancer patients with Gleason score8-10 treated with definitive radiotherapy : TROD 09-001 multi-institutional study.

Abstract

To validate the clinical outcomes and prognostic factors in prostate cancer (PCa) patients with Gleason score (GS)8-10 disease treated with external beam radiotherapy (EBRT) + androgen deprivation therapy (ADT) in the modern era. Institutional databases of biopsy proven 641 patients with GS8-10PCa treated between 2000 and 2015 were collected from 11institutions. In this multi-institutional Turkish Radiation Oncology Group study, astandard database sheet was sent to each institution for patient enrollment. The inclusion criteria were, T1-T3N0M0 disease according to AJCC (American Joint Committee on Cancer) 2010 Staging System, no prior diagnosis of malignancy, at least 70 Gy total irradiation dose to prostate ± seminal vesicles delivered with either three-dimensional conformal RT or intensity-modulated RT and patients receiving ADT. The median follow-up time was 5.9years (range 0.4-18.2years); 5‑year overall survival (OS), biochemical relapse-free survival (BRFS) and distant metastases-free survival (DMFS) rates were 88%, 78%, and 79%, respectively. Higher RT doses (≥78 Gy) and longer ADT duration (≥2years) were significant predictors for improved DMFS, whereas advanced stage was anegative prognosticator for DMFS in patients with GS9-10. Our results validated the fact that oncologic outcomes after radical EBRT significantly differ in men with GS8 versus those with GS9-10 prostate cancer. We found that EBRT dose was important predictive factor regardless of ADT period. Patients receiving 'non-optimal treatment' (RT doses <78 Gy and ADT period <2years) had the worst treatment outcomes.