PurposeFor men with intermediate risk prostate cancer treated with definitive therapy, the addition of androgen deprivation therapy (ADT) reduces the risk of distant metastasis and cancer-related mortality. However, the absolute benefit of ADT varies by baseline cancer risk. Estimates of prognosis have improved over time, and little is known about ADT decision making in the modern era. We sought to characterize variability and identify factors associated with intended ADT use within the [statewide quality consortium]. Materials and MethodsPatients with localized prostate cancer undergoing definitive radiotherapy were enrolled from 6/9/20 to 6/26/23 (n=815). Prospective data was collected using standardized patient, physician, and physicist forms. Intended ADT use was prospectively defined and is the primary outcome. Associations with patient, tumor, and practice-related factors were tested with multivariable analyses (MVA). Random intercept modeling was used to estimate facility-level variability. ResultsFive-hundred seventy patients across 26 facilities were enrolled with intermediate risk disease. ADT was intended for 46% of men (n=262/570), which differed by NCCN favorable intermediate-risk (FIR) (23.5%, n=38/172) vs unfavorable intermediate-risk (UIR) disease (56.3%, n=224/398), p<0.001. After adjusting for the statewide case mix, the predicted probability of intended ADT use varied significantly across facilities, ranging from 15.4% (95% CI 5.4-37.0%) to 71.7% (95% CI 57.0-82.9%), p<0.01. MVA showed that grade group 3 (OR 4.60 [3.20-6.67]), ≥50% positive cores (OR 2.15 [1.43-3.25]), and PSA 10-20 (OR 1.87 [1.24-2.84]) were associated with ADT use. AUC was improved when incorporating MRI adverse features (0.76) or radiation treatment variables (0.76), but there remained significant facility level heterogeneity in all models evaluated (p<0.05). ConclusionsWithin a state-wide consortium, there is substantial facility-level heterogeneity in intended ADT use for men with intermediate risk prostate cancer. Future efforts are necessary to identify patients who will benefit most from ADT and to develop strategies to standardize appropriate use.