Understanding the impact of historical redlining on prostate cancer care quality and treatment patterns and the association with modern metrics of disparity.

118 Background: Sociodemographic and racial disparities persist in prostate cancer care, including associations between place-based indices and prostate cancer care quality and treatment modality. This study examines the impact of historical redlining conducted by the Home Owner’s Loan Corporation (HOLC) in 1933 on modern prostate cancer care quality. Methods: We performed a retrospective, observational cohort study utilizing Medicare claims data (2015-2019) of patients aged 66 or older with localized prostate cancer. ArcGIS was used to overlay HOLC grading to modern five-digit zip-codes and generate a weighted average HOLC grade for each zip. Data was then merged with modern metrics of social determinants of health including social vulnerability index (SVI) and dual eligibility. In order to assess historical and modern metrics of structural racism, patients across HOLC grade were compared to determine treatment modality and access to prostate cancer care quality. HOLC grade was then compared to SVI and dual eligibility in determining disparities. Results: We identified 14,630 patients with newly diagnosed prostate cancer who reside within an area that received a HOLC grade, of whom 10187 (70%) were white, 2910 (20%) were Black, and 1473 (10%) were another race or ethnicity. Patients in HOLC-graded areas were more likely to be socioeconomically disadvantaged (dual eligibility status, 11% vs. 4.1%, p<0.001; 4 th Quartile SVI; 36% vs. 24%, p<0.001) and urban residents (99.9% vs 76%, p<0.001). Multivariable logistic regression analysis of patients who resided in HOLC-graded areas indicated that those in areas with worse HOLC-grade (per 1-grade difference) had lower odds of undergoing surgery (OR 0.89, CI 0.83-0.96, p=0.003), being treated by a high-volume practitioner (OR 0.86 CI 0.81-0.92, p<0.001), or undergoing pre-biopsy MRI (OR 0.94, CI 0.89-1.0, p=0.050), but similar odds of being seen by both a radiation oncologist and urologist (OR 1.03, CI 0.96-1.11, p=0.5). No significant interactions between HOLC grade and social vulnerability were found. Conclusions: This study reveals the enduring impact of historical redlining on prostate cancer care disparities, emphasizing the need for targeted interventions and housing policy reforms to promote equitable access to care. Racially explicit policies continue to shape healthcare disparities, independent of contemporary socioeconomic factors.