Improved survival with the addition of radiotherapy to androgen deprivation: questions answered and a review of current controversies in radiotherapy for non-metastatic prostate cancer

The contemporary standard of care for locally advanced high-risk prostate cancer includes a combination of dose-escalated radiotherapy (RT) plus androgen-deprivation therapy (ADT). However, 20 years ago, at the inception of the National Cancer Institute of Canada (NCIC) led study (NCIC Clinical Trials Group PR.3/Medical Research Council PR07/Intergroup T94-0110), the survival impact of prostate RT for high-risk disease was uncertain. Recently, Mason, Warde and colleagues presented the final results of this NCIC/MRC study (PMID: 25691677) randomizing 1,205 high-risk prostate cancer patients to ADT + RT vs. ADT alone. These updated results confirm substantial improvements with the addition of RT to ADT for the endpoints of overall survival (OS), disease-free survival (DFS), and biochemical recurrence. Close examination of subtleties of this trial’s design highlight some of the most salient controversies in the field of prostate RT, including the risk-stratified roles of ADT, optimal ADT duration, and RT field design in the dose-escalated and intensity-modulated radiotherapy (IMRT) era.