Mediators of Racial Disparity in the Use of Prostate Magnetic Resonance Imaging Among Patients With Prostate Cancer.

IMPORTANCE

Racial disparity in the use of prostate magnetic resonance imaging (MRI) presents obstacles to closing gaps in prostate cancer diagnosis, treatment, and outcome.

OBJECTIVE

To identify clinical, sociodemographic, and structural processes underlying racial disparity in the use of prostate MRI among men with a new diagnosis of prostate cancer.

DESIGN, SETTING, AND

PARTICIPANTS

This population-based cohort study used mediation analysis to assess claims in the US Surveillance, Epidemiology, and End Results (SEER)-Medicare database for prostate MRI among 39 534 patients with a diagnosis of localized prostate cancer from January 1, 2011, to December 31, 2015. Statistical analysis was performed from April 1, 2020, to September 1, 2021.

EXPOSURE: Diagnosis of prostate cancer.

MAIN OUTCOMES AND MEASURES: Claims for prostate MRI within 6 months before or after diagnosis of prostate cancer were assessed. Candidate clinical and sociodemographic meditators were identified based on their association with both race and prostate MRI, including the Index of Concentration at the Extremes (ICE), as specified to measure racialized residential segregation. Mediation analysis was performed using nonlinear multiple additive regression trees models to estimate the direct and indirect effects of mediators.

RESULTS

A total of 39 534 eligible male patients (3979 Black patients [10.1%] and 32 585 White patients [82.4%]; mean [SD] age, 72.8 [5.3] years) were identified. Black patients with prostate cancer were less likely than White patients to receive a prostate MRI (6.3% vs 9.9%; unadjusted odds ratio, 0.62, 95% CI, 0.54-0.70). Approximately 24% (95% CI, 14%-32%) of the racial disparity in prostate MRI use between Black and White patients was attributable to geographic differences (SEER registry), 19% (95% CI, 11%-28%) was attributable to neighborhood-level socioeconomic status (residence in a high-poverty area), 19% (95% CI, 10%-29%) was attributable to racialized residential segregation (ICE quintile), and 11% (95% CI, 7%-16%) was attributable to a marker of individual-level socioeconomic status (dual eligibility for Medicare and Medicaid). Clinical and pathologic factors were not significant mediators. In this model, the identified mediators accounted for 81% (95% CI, 64%-98%) of the observed racial disparity in prostate MRI use between Black and White patients.

CONCLUSIONS AND RELEVANCE: In this this population-based cohort study of US adults, mediation analysis revealed that sociodemographic factors and manifestations of structural racism, including poverty and residential segregation, explained most of the racial disparity in the use of prostate MRI among older Black and White men with prostate cancer. These findings can be applied to develop targeted strategies to improve cancer care equity.