Lack of Apparent Survival Benefit from the Use of Androgen Deprivation Therapy in Patients with High-Risk Prostate Cancer Treated with Combined External Beam Radiotherapy and Brachytherapy

Publication date: Available online 9 September 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): David D. Yang, Vinayak Muralidhar, Brandon A. Mahal, Paul L. Nguyen, Phillip M. Devlin, Martin T. King, Peter F. Orio
PurposeWhile level 1 evidence has demonstrated a survival benefit from the addition of androgen deprivation therapy (ADT) to external beam radiation therapy (EBRT) for patients with high-risk prostate cancer, the benefits of ADT with combined EBRT and brachytherapy for high-risk patients are unclear. We examined the association between ADT and overall survival in a national cohort of high-risk patients treated with EBRT with or without brachytherapy.Methods and MaterialsWe identified 46,325 men in the National Cancer Database diagnosed from 2004 through 2011 with high-risk prostate cancer (Gleason 8-10, clinical T3-4, or prostate-specific antigen >20 ng/mL) who were treated with EBRT with or without brachytherapy and ADT. Multivariable Cox regression adjusting for sociodemographic and clinicopathologic factors was used to identify the association between ADT and overall survival.ResultsMedian follow-ups were 48.6 and 59.2 months for patients treated with EBRT only and combined modality radiotherapy, respectively. ADT was associated with an improvement in overall survival for the 85.0% (39,361) of the study cohort managed with EBRT alone (adjusted hazard ratio 0.91, P=0.001) but not for patients treated with combined modality radiotherapy (adjusted hazard ratio 1.05, P=0.496), with a significant interaction (Pinteraction=0.036).ConclusionsAs opposed to the known survival benefit when ADT is given with EBRT, our results suggest that ADT may not improve survival for high-risk patients treated with combined EBRT and brachytherapy. Given the significant adverse effects of ADT, particularly long-term therapy, a randomized controlled trial of combined EBRT and brachytherapy with or without ADT for select high-risk patients using a non-inferiority design should be undertaken.

Teaser

The benefits of androgen deprivation therapy (ADT) with combined external beam radiotherapy and brachytherapy for patients with high-risk prostate cancer are unknown. Using a large, national cohort of high-risk patients, we found that ADT was associated with an improvement in overall survival for patients managed with EBRT alone but not for patients treated with combined modality radiotherapy, suggesting that ADT may not improve overall survival for select high-risk patients treated with combined modality radiotherapy.


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