Quality of treatment with targeted agents for advanced prostate cancer by treating specialist.

Abstract

88 Background: Urologists are increasingly prescribing oral targeted agents to men with advanced prostate cancer, who traditionally have been cared for by medical oncologists. These agents require close monitoring, since they mechanistically affect androgen biosynthesis and can lead to cardiovascular and metabolic adverse events. It is unclear whether patients treated by urologists—whose practice scope typically does not involve systemic therapies—experience more frequent therapy-related adverse events. Further, these medications are expensive, often subjecting patients to high out-of-pocket costs, which can lead to coping strategies like treatment non-adherence. Urologists may have less experience discussing these costs and exploring cheaper alternatives. Methods: A 20% sample of National Medicare claims was used to perform a retrospective cohort study of Medicare beneficiaries with advanced prostate cancer between 2012-2020 who were treated with a targeted agent (abiraterone or androgen receptor blocker). The primary outcome was the composite of any hospital or emergency department visit for a cardiometabolic event within 1 year of starting a targeted agent. Secondary outcomes included monthly out-of-pocket costs in those without low-income subsidies and adherence to treatment in first 6 months after initiating treatment. Multivariable regression models were fitted to assess the association between prescribing specialist (urologist or medical oncologist) and each outcome. Results: There were 1,462 (25%) and 4,501 (75%) patients who were prescribed a targeted agent by a urologist and medical oncologist. Men who were managed by urologists were more often started on an androgen receptor blocker, compared to those managed by medical oncologists (67% vs 36%, p<0.001).There were no differences in the adjusted frequencies of composite adverse events of patients managed by urologists and medical oncologists in those who were started on abiraterone (7.7 % vs 8.1%, P=0.79) or an androgen receptor blocker (6.4% vs 6.2%, p=0.91). Out-of-pocket costs did not vary between patients who were managed by urologists vs medical oncologists in those who were started on abiraterone ($748 % vs $778%, P=0.48) or an androgen receptor blocker ($795 vs $834, p=0.33). Adherence to treatment was similar between the specialties in those prescribed abiraterone (67% vs 64%, P=0.15), but the likelihood of adherence was higher in men prescribed an androgen receptor blocker by a urologist (65% vs 61%, p=0.04). Conclusions: Although urologists may be less accustomed to primarily managing advanced prostate cancer than medical oncologists, patients fared no worse when assessing adverse events, out-of-pocket costs, or adherence to treatment. This study provides further support for urologists’ increased role in managing advanced prostate cancer.