Lack of Benefit for the Addition of Androgen Deprivation Therapy to Dose-Escalated Radiotherapy in the Treatment of Intermediate- and High-Risk Prostate Cancer

Abstract

Assessment of androgen deprivation therapy (ADT) benefits for prostate cancer treated with dose-escalated radiotherapy (RT). From 1991 to 2004, 1,044 patients with intermediate- (n = 782) or high-risk (n = 262) prostate cancer were treated with dose-escalated RT at William Beaumont Hospital. Patients received external-beam RT (EBRT) alone, brachytherapy (high or low dose rate), or high dose rate brachytherapy plus pelvic EBRT. Intermediate-risk patients had Gleason score 7, prostate-specific antigen (PSA) 10.0-19.9 ng/mL, or Stage T2b-T2c. High-risk patients had Gleason score 8-10, PSA ≥20, or Stage T3. Patients were additionally divided specifically by Gleason score, presence of palpable disease, and PSA level to further define subgroups benefitting from ADT. Median follow-up was 5 years; 420 patients received ADT + dose-escalated RT, and 624 received dose-escalated RT alone. For all patients, no advantages in any clinical endpoints at 8 years were associated with ADT administration. No differences in any endpoints were associated with ADT administration based on intermediate- vs. high-risk group or RT modality when analyzed separately. Patients with palpable disease plus Gleason ≥8 demonstrated improved clinical failure rates and a trend toward improved survival with ADT. Intermediate-risk patients treated with brachytherapy alone had improved biochemical control when ADT was given. Benefits of ADT in the setting of dose-escalated RT remain poorly defined. This question must continue to be addressed in prospective study.