Factors associated with the omission of androgen deprivation therapy in radiation-managed high-risk prostate cancer

Purpose Androgen deprivation therapy (ADT) has been shown to improve survival for men with unfavorable-risk prostate cancer (PCa). We investigated the utilization and factors associated with the omission of ADT in radiation-managed high-risk PCa. Methods and Materials We used the National Cancer Database to identify men with National Comprehensive Cancer Network high-risk PCa treated with external beam radiation therapy (EBRT) with or without brachytherapy boost from 2004 to 2012. Multivariable logistic regression adjusting for clinical and sociodemographic factors was used to identify independent predictors for ADT use. Results A total of 57,968 radiation-treated high-risk PCa men were included in our analysis. There were 49,363 patients (85.2%) treated with EBRT alone and 8605 patients (14.8%) treated with EBRT plus brachytherapy boost. Overall, 77% of men received ADT. In multivariable regression analysis, the use of brachytherapy boost was associated with a significantly lower utilization of ADT (70% vs. 78%; adjusted odds ratio [AOR]: 0.65; 95% CI: 0.62–0.69; p-Value <0.0001), as was treatment at an academic vs. nonacademic center (AOR: 0.90; 95% CI: 0.86–0.95; p-Value <0.0001) and treatment in 2010–2012 compared to 2004–2006 (AOR: 0.85; 95% CI: 0.81–0.90; p-Value <0.0001). Conversely, greater ADT use was seen with higher Gleason scores, PSA, and T-category (all p-Values <0.001). Conclusions Approximately one in four men with radiation-managed high-risk PCa do not receive ADT, which may reflect concerns about its toxicity profile despite known improvements in overall survival. Practice patterns suggest that some providers believe dose escalation through brachytherapy boost may obviate the need for ADT in some high-risk patients, but this hypothesis requires further testing.