Main Session
Sep 29
PQA 06 - Genitourinary Cancer, Gynecological Cancer, and Health Care Access and Engagement

3712 - Prior Primary Care Utilization and Racial Disparities in Breast Cancer Metastatic Presentation and Mortality

02:15pm - 03:30pm ET
Poster Hall - Exhibit Hall A
Screen: 32
POSTER

Presenter(s)

Sakshith Reddy Chintala, MS - University of California San Diego, La Jolla, CA

S. R. Chintala1,2, E. M. Qiao1, K. M. Morgan1, D. Sabater Minarim1,2, H. Nguyen1,3, N. V. Kalahasti3, M. Banegas1,2, C. R. Nwachukwu2,4, and B. S. Rose1,2; 1Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA, 2Center for Health Equity, Education and Research, University of California San Diego, La Jolla, CA, 3University of California San Diego School of Medicine, La Jolla, CA, 4Department of Radiation Oncology, University of California San Diego, La Jolla, CA

Purpose/Objective(s):

Black women experience higher breast cancer mortality compared to non-Hispanic White (NHW) women, yet the contribution of pre-diagnostic primary care to these disparities remains unclear. We hypothesized that differences in primary care provider (PCP) engagement and screening mammography prior to diagnosis mediate a significant proportion of the racial disparity in metastatic presentation and cancer-specific mortality (CSM) between Black and NHW women.

Materials/Methods:

We performed a retrospective analysis of Black and NHW women aged =68 diagnosed with breast cancer (2010-2017) using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. PCP utilization was measured as years with =1 PCP visit in the 3 years pre-diagnosis: none (0), partial (1-2), or annual (3). Screening mammography was similarly categorized. Logistic regression estimated odds of metastatic disease at diagnosis. Fine-Gray competing risk models estimated subdistribution hazard ratios (SHR) for CSM with non-cancer death as competing event. Models were sequentially adjusted: unadjusted, clinical/demographic factors, PCP visits, and mammography. Baron-Kenny mediation analysis quantified the proportion of the racial disparity explained by healthcare access.

Results:

Among 38,012 patients (3,335 Black; 34,677 NHW), Black women had higher rates of metastatic disease (9.2% vs 5.3%) and no prior PCP visits (11.1% vs 5.6%). Any PCP utilization was associated with 52-54% lower odds of metastatic disease and 41-48% lower CSM risk versus no prior visits. On unadjusted analysis, Black women had 80% higher odds of metastatic disease (OR 1.80). After adjusting for tumor biology and demographics, this decreased to 38% (OR 1.38, 95% CI 1.20-1.59), and further to 26% after adding PCP and mammography (OR 1.26, 95% CI 1.09-1.45). For CSM, the unadjusted 78% higher risk (SHR 1.78) decreased to 29% after clinical adjustment (SHR 1.29, 95% CI 1.19-1.41) and 21% after adding healthcare access (SHR 1.21, 95% CI 1.11-1.31). Mediation analysis showed PCP visits mediated 31.7% of the stage disparity and 29.2% of the CSM disparity; mammography alone mediated 10.8% and 6.4%, respectively.

Conclusion:

Pre-diagnostic PCP utilization mediates approximately 30% of the Black-NHW disparity in metastatic breast cancer presentation and mortality. PCP engagement showed stronger mediation than mammography alone, suggesting primary care relationships confer benefits beyond cancer screening. Policies to improve PCP access among Black women represent an actionable intervention to reduce breast cancer outcome disparities.