Androgen Deprivation Therapy Practice Patterns in High-Risk Prostate Cancer Treated With Definitive Radiotherapy: Prospective Results From a Statewide Quality Consortium

PURPOSE The 2022 AUA/ASTRO guidelines recommend 18-36 months of androgen deprivation therapy (ADT) with definitive radiotherapy for localized, high-risk prostate cancer. The STAMPEDE M0 trial supports intensification with androgen receptor pathway inhibitors (ARPIs) for patients with ≥2 cT3/T4, Grade Group [GG] 4-5, prostate-specific antigen (PSA) ≥40 ng/mL, or cN1. Given advances in imaging, risk stratification, and treatment delivery, we characterized contemporary practice patterns using prospective data from the Michigan Radiation Oncology Quality Consortium (MROQC). METHODS Patients enrolled in MROQC with intact, high-risk M0/N0-1 prostate cancer were included. Clinical information, including intended ADT duration and ARPI use, was prospectively collected. The primary outcome was intended guideline-concordant ADT (GC-ADT, ≥18 months). Multivariable analyses (MVA) assessed associations between clinical factors and GC-ADT recommendations. We compared the adoption of ARPI with standard therapies before and after the publication of STAMPEDE M0. Facility-level variability was evaluated using a mixed-effects model, with the treatment site as a random intercept. RESULTS Between June 2020 and November 2024, 553 patients across 26 centers were included: cT3/4 (13.3%), cN1 (19.9%), GG 4-5 (75.0%), and PSA ≥20 ng/mL (40.0%). Overall, 91.3% were recommended ADT, with 67.0% being guideline-concordant. On MVA, GC-ADT was significantly associated with cN1 (odds ratio [OR], 2.94 [95% CI, 1.44 to 5.99]), GG (GG4 OR, 6.23 [95% CI, 2.85 to 13.62]; GG5 OR, 9.45 [95% CI, 4.46 to 20.06]), and PSA ≥40 (OR, 3.64 [95% CI, 1.22–10.87]). Facility-level variability persisted in the MVA ( P < .0001). Among the 27.9% who met meeting STAMPEDE criteria, ARPI recommendations increased from 0% prepublication to 23.2% afterward. CONCLUSION Within a statewide quality consortium, guideline-concordant ADT recommendations occurred in two thirds of patients, with ARPI intensification in under 25% among STAMPEDE-eligible patients. These findings highlight the need for individualized ADT strategies and collaborative efforts to standardize high-quality care.