Effect of equal access to care on prostate cancer progression in minority patients.

Abstract

33 Background: Prostate cancer (PC) is an androgen-dependent disease that initially responds to androgen deprivation therapy (ADT); however, it can become resistant to therapies that reduce testosterone levels, signaling a transition to non-metastatic, castration-resistant PC (nmCRPC). Racial disparities are known in PC, with black and Hispanic men presenting with more advanced disease and having a higher mortality rate compared to non-Hispanic white men. The goal of treatment management in patients with nmCRPC is to prevent or delay metastases. This study examines the disease progression observed among patients with nmCRPC who received care and treatment in an equal access healthcare system, the Veterans Health Administration. Methods: Patient information was obtained from the Veterans Affairs (VA) Clinical Cancer Registry (VACCR) and the VA Corporate Data Warehouse (CDW) to identify patients who were diagnosed with prostate cancer at the VA and later developed nmCRPC, defined as (1) evidence of a rising prostate-specific antigen (PSA), i.e., 2 consecutive increases in PSA concentration over a baseline value; (2) evidence of ongoing androgen deprivation consisting of a serum testosterone level of ≤50 ng/dL (≤2.0 nmol/L); and (3) the absence of metastatic disease as evidenced in radiology reports. Treatments of nmCRPC were identified by review of NCCN Prostate Cancer Guidelines and extracted from CDW pharmacy dispensation records and indexed at nmCRPC diagnosis. A multivariate Cox proportional hazard model was used to identify time to metastatic disease in nmCRPC patients. Results: 654,148 patients were diagnosed with PC and received care in the VA from 2006 to 2021; of these, 12,992 developed nmCRPC, of whom 7,323 (56%) were white, 3,671 (28%) were black, 826 (6%) were Hispanic, and 1,172 (9%) were reported as other. Compared with white men at nmCRPC diagnosis, black men were younger (70 years vs. 74 years) while Hispanic men were older (75 years). White and Hispanic men had similar PSA at nmCRPC (10.2 ng/mL and 10.4 ng/mL), while the PSA for black men was higher (14.3 ng/mL). Similar treatment patterns were observed in all patients regardless of race; with ADT (60%), bicalutamide (24%), and finasteride (3%), the most frequently used first-line treatments. The mean time from nmCRPC to metastatic CRPC was 27.5 days for white men, 31.6 days for black men, 27.6 for Hispanic men, and 26.0 days for others. After adjusting for age, comorbidities, PSA doubling time, and treatment, the hazard ratio (HR) for developing metastatic disease was 0.85 (95% CI: 0.80–0.90, <0.001) for black men, 0.70 (95% CI: 0.62–0.78, <0.001) for Hispanic men, and 1.07 (95% CI: 0.99–1.16, <0.001) for others. Conclusions: These results suggest that when provided with care and treatment in an equal access healthcare system, black and Hispanic patients with nmCRPC are less likely to progress to metastatic CRPC than non-Hispanic white men.