PROJECT SUMMARY/ABSTRACT Prostate cancer is a significant public health burden with substantial heterogeneity in clinical outcomes and large racial disparities: Black men in the United States are 1.6 times more likely to be diagnosed with prostate cancer and two times more likely to die from prostate cancer compared to white men. Patients with advanced prostate cancer (APC) experience the highest risk of death and the most severely impacted quality of life due to the disease itself as well as its associated therapies. Despite this, advanced prostate cancer is understudied. The treatment landscape for APC has changed rapidly over the past 10 years with the FDA approval of 11 new therapies in the US, yet the real-world uptake of these therapies and experience of men using these therapies is unknown. Additionally, though disparities in access to treatment and quality of life have been shown in patients with localized prostate cancer, these outcomes have not been studied in patients with APC; this is concerning as limited access to treatment and poorer quality of life have been linked to higher mortality in cancer broadly. Little is known about the treatment patterns for or experience of patients with APC, and most studies to date in this population have enrolled primarily non-Hispanic white men. There is an urgent need to expand the investigation of prostate cancer racial disparities into patients with APC, and with a specific focus on patient-centric outcomes, to highlight potential areas for intervention to decrease mortality from APC. The overarching goal of the proposed work is to quantify racial differences in the treatment patterns, experience with the health care system, and quality of life for patients with APC in the United States and United Kingdom. I will investigate these domains of the patient experience using data from approximately 1500 patients enrolled in the International Registry for Men with Advanced Prostate Cancer (IRONMAN), a global prospective cohort of men newly diagnosed with APC. Specifically, I will compare the self-identified races of Black and white men in the US and UK. In Aim 1, I will use medical record and physician questionnaire data to characterize differences in observed treatment patterns and reasons for discontinuing treatments. In Aim 2, I will use Australia’s National Cancer Control Indicators to assess differences in baseline patient experience with the health care system, emphasizing communication and integration into care. In Aim 3, I will use patient-reported outcome measures data from the EORTC QLQ-C30 Quality of Life Survey to assess racial differences in baseline and longitudinal domains of quality of life, including overall quality of life, functional status, and symptom status. This project will provide real-world information that can be directly translated by identifying and quantifying racial disparities across the spectrum of care received by patients with APC, suggesting potential areas for inter...