The decreased use of brachytherapy boost for intermediate and high-risk prostate cancer despite evidence supporting its effectiveness

Abstract

Purpose: The Canadian Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy (ASCENDE-RT) randomized trial showed that brachytherapy boost reduces recurrence by 50% compared to dose-escalated radiation. We examined how men with identical inclusion criteria to the ASCENDE-RT trial were being treated in the United States.

Methods and materials: We used the National Cancer Database to identify prostate cancer patients treated with radiation from 2004 through 2012 who met the inclusion criteria of the ASCENDE-RT trial (intermediate-/high-risk prostate cancer, excluding patients with prostate-specific antigen >40 or tumor stage T3b/T4). The Mantel-Haenszel test was used to investigate the trend for type of radiation modality used over the study period.

Results: A cohort of 156,411 patients was identified. Of those, 103,188 men (66%) were treated with external beam radiation therapy (EBRT) alone, 31,129 (20%) with brachytherapy alone, and 22,094 (14%) with EBRT plus brachytherapy. EBRT plus a brachytherapy boost demonstrated a significant decrease in utilization from 2004 to 2012 in both academic and nonacademic centers, declining from 15% to 8% in academic centers and from 19% to 11% in nonacademic centers (p-Value for trend <0.0001 for both). Academic centers were significantly less likely to use brachytherapy boost than nonacademic centers (adjusted odds ratio: 0.68; 95% confidence interval: 0.66-0.70; p-Value: <0.0001).

Conclusions: Radiation oncology practices have demonstrated a significant reduction in the use of brachytherapy boost from 2004 to 2012, and the lowest utilization was in academic centers. In light of the superior results demonstrated for brachytherapy boost by the ASCENDE-RT trial, it is unclear whether academic centers are prepared to train the next generation of residents in this critical modality.

Keywords: ASCENDE-RT; Brachytherapy boost; National cancer database; Prostate cancer; Radiation therapy.