Abstract
INTRODUCTION: Treatment intensification with androgen receptor signaling inhibitors and/or chemotherapy is guideline recommended for patients with de novo metastatic hormone-sensitive prostate cancer (mHSPC). However, most patients only receive androgen deprivation therapy monotherapy. The aim was to identify physician-, patient-, and tumor-related factors associated with the receipt of treatment intensification. METHODS: A population-based cohort study was conducted in Ontario, Canada, which included men ≥66 years newly diagnosed with de novo mHSPC between January 2014 and December 2022. Hierarchical regression modeling was used to examine the association of physician, patient, and tumor characteristics with the receipt of treatment intensification, defined as the initiation of an androgen receptor signaling inhibitor, docetaxel, or both within six months of diagnosis. Darlington's method was used to assess predictor importance via standardized regression coefficients (SRC). RESULTS: Among 6099 eligible older men newly diagnosed with de novo mHSPC, 1475 (24.2%) received treatment intensification. In multivariable modeling, patients initiated on androgen deprivation therapy by radiation oncologists were less likely to receive treatment intensification (odds ratio [OR]. 0.48; 95% CI, 0.37-0.61; p < .01; SRC: 19.46; p < .01) whereas those by medical oncologists were more likely to receive treatment intensification (OR, 1.64; 95% CI, 1.21-2.22; p < .01; SRC: 9.56; p < .01), each compared to urologists. Older patients were significantly less likely to receive treatment intensification (OR 0.94 per year over age 66; 95% CI, 0.93-0.95; p < .01; SRC: -36.21; p < .01). CONCLUSION: Patient and physician characteristics significantly influence variation in the use of treatment intensification for de novo mHSPC. These findings inform targeted interventions and policies to enhance the delivery of life-prolonging mHSPC care.