Treatment intensification in veterans with metastatic prostate cancer.

Abstract

e13785 Background: Treatment intensification with androgen receptor pathway inhibitors (ARPIs) or chemotherapy in addition to traditional androgen deprivation (ADT) extends survival and is standard of care for men with metastatic castration sensitive prostate cancer (mCSPC). However, treatment with ARPIs or chemotherapy is underused; less than half of men with mCSPC receive treatment intensification in the community. This study investigated clinical and social factors associated with treatment intensification among Veterans treated in the VA. Methods: We used a natural language processing tool to identify Veterans diagnosed with mCSPC between January 1, 2023, and June 17, 2024, who were continuously followed in the VA for ≥2 years prior to metastatic diagnosis, did not receive systemic therapy for prostate cancer the year prior, and started ADT within six months of metastatic diagnosis. We used the VA Corporate Data Warehouse linked to Medicare and the US Vets database to extract treatment received, clinical characteristics at the time of diagnosis (i.e., comorbidity and cancer characteristics – prostate specific antigen levels and de novo metastatic versus recurrent metastatic), and social factors such as race and income. We used multivariable logistic regression to estimate predicted probabilities for treatment intensification (i.e., ADT plus ARPI [abiraterone, enzalutamide, apalutamide, darolutamide] and/or docetaxel) versus ADT alone within six months of metastatic diagnosis. Results: We identified 2540 Veterans with mCSPC who met eligibility criteria. After adjusting for other clinical and social characteristics, we saw a similar predicted probability of receiving treatment intensification for Veterans under 80 (69% at age 50 and 60, 68% at age 70, 67% at age 80), but this dropped off after age 80 with predicted probability below 60% at age 85, and below 40% at age 91 (p < 0.01). Veterans with Charlson comorbidity index (CCI) ≥ 2 had a predicted probability of receiving treatment intensification of 59% versus 68% for those with CCI = 0 (p < 0.01). Higher prostate specific antigen level and de novo metastatic versus recurrent disease were each associated with greater probability of receiving treatment intensification. Black Veterans had a lower predicted probability of receiving treatment intensification compared to White Veterans (61% vs. 66%, p = 0.02). Veterans with income > $100,000 trended toward a greater predicted probability of receiving treatment intensification compared to Veterans with incomes < $15,000 (69% vs. 61%, p = 0.08). Conclusions: Men with mCSPC had a higher rate of treatment intensification in the VA than prior studies of men with mCSPC in the community; however, rates of treatment intensification remain low, and Black Veterans were still less likely to receive this standard of care despite adjustment for comorbidity, disease characteristics, and other social factors.