Variations in patterns of concurrent androgen deprivation therapy use based on dose escalation with external beam radiotherapy vs. brachytherapy boost for prostate cancer

Abstract

PurposeRetrospective data suggest less benefit from androgen deprivation therapy (ADT) in the setting of dose-escalated definitive radiation for prostate cancer, especially when a combination of external beam radiotherapy (EBRT) and brachytherapy approaches are used. This study aimed to test the hypothesis that patients with prostate cancer with intermediate- or high-risk disease undergoing extreme dose escalation with a brachytherapy boost are less likely to receive ADT. Methods and MaterialsData from the National Cancer Database were extracted for men aged 40–90 years diagnosed with node-negative, non-metastatic prostate cancer from 2004 to 2015. Only patients with intermediate- or high-risk disease who were treated with definitive radiotherapy were included. The association and patterns of care between dose escalated radiotherapy and ADT receipt were assessed using multivariable logistic regression. ResultsPatients with unfavorable intermediate- and high-risk prostate cancer were significantly less likely to receive ADT if they underwent dose escalation with a combination of EBRT and brachytherapy (odds ratio 0.67, p < 0.0001). Over time, this decrease in ADT utilization has widened for patients with unfavorable intermediate-risk disease. There was no difference in ADT utilization when comparing patients treated with non–dose-escalated EBRT to those treated with dose-escalated EBRT (without brachytherapy). ConclusionIn this large national database, patients with unfavorable intermediate- and high-risk prostate cancer were significantly less likely to receive guideline-indicated ADT if they underwent extreme dose escalation with combined radiation modalities. As we await prospective data guiding the utility of ADT with dose escalated radiation, these findings suggest potential underutilization of ADT in patients at higher risk of advanced disease.