Practice patterns and predictors of treatment intensification in patients with metastatic castration-sensitive prostate cancer

Introduction: Treatment intensification beyond androgen deprivation therapy (ADT) has shown survival benefit in patients with metastatic castration-sensitive prostate cancer (mCSPC). There is a need to better understand how these novel treatments fit in real-world practice. Methods: Using electronic medical records and administrative data, a population-based, retrospective cohort study of patients newly diagnosed with de novo mCSPC between 2010 and 2020 in Alberta, Canada, and initiated ADT was conducted. Treatment intensification was defined as the receipt of apalutamide, abiraterone acetate, enzalutamide, or chemotherapy (e.g., docetaxel) within 180 days of ADT initiation. Results: A total of 2515 de novo mCSPC were identified, with 2098 (83%) patients initiating ADT post-diagnosis. Of those, 525 (25%) received intensification beyond ADT. The percentage of patients who were intensified was 3% in 2010–2013 and gradually increased to 67% in 2020. From 2014–2017, docetaxel was the most commonly used approach, although it was supplanted by abiraterone acetate, apalutamide and enzalutamide from 2018 onwards. In multivariable logistic regression analyses of patients diagnosed from 2014–2020, significant predictors of intensification were younger age at diagnosis, lower Charlson comorbidity index, greater number of metastatic sites, shorter time to ADT initiation, referral to a medical oncologist, transurethral resection of the prostate or radiation prior to ADT, and more recent year of diagnosis (all p<0.05). Intensification increased for patients living in rural areas and with higher disease burden in 2018+ compared to 2014–2017. Conclusions: There has been a considerable increase in the use of ADT intensification therapies that correspond with the timing of clinical trial data and approvals of novel agents.