Brachytherapy boost for prostate cancer: Trends in care and survival outcomes

Androgen suppression combined with elective nodal and dose-escalated radiation therapy recently demonstrated an improved biochemical failure-free survival in men who received external beam radiation therapy (EBRT) plus a brachytherapy boost (BB) compared with dose-escalated external beam radiotherapy (DE-EBRT). We sought to analyze the factors predictive for use of EBRT + BB as compared with DE-EBRT and report resulting survival outcomes on a national level using a hospital-based registry.

We identified 113,719 men from the National Cancer Database from 2004 to 2013 with intermediate- or high-risk prostate cancer who were treated with EBRT + BB or DE-EBRT. We performed univariate and multivariate analyses of all available factors potentially predictive of receipt of treatment selection. Survival was evaluated in a multivariable model with propensity adjustment.

For intermediate-risk patients, utilization of BB decreased from 33.1% (n = 1742) in 2004 to 12.5% (n = 766) in 2013 and for high-risk patients, utilization dropped from 27.6% (n = 879) to 10.8% (n = 479). Numerous factors predictive for use of BB were identified. Cox proportional hazards analysis was performed-adjusting for age, Charlson-Deyo comorbidity score, T stage, prostate-specific antigen, Gleason score, and sociodemographic factors-and demonstrated BB use was associated with a hazard ratio of 0.71 (95% confidence interval, 0.67-0.75; p < 0.0005) and 0.73 (95% confidence interval, 0.68-0.78; p < 0.0005) for intermediate- and high-risk patients, respectively.

There has been a concerning decline in the utilization of BB for intermediate- and high-risk prostate cancer patients despite an association with improved on overall survival. Numerous factors predictive for use of BB have been identified.