Purpose: To assess trends and rural-urban disparities in palliative care utilization among patients with metastatic breast cancer.

Methods: We analyzed data from the 2004-2019 National Cancer Database. Palliative care services, including surgery, radiotherapy, systemic therapy, and/or other pain management, were provided to control pain or alleviate symptoms; utilization was dichotomized as "yes/no." Rural-urban residence, defined by the US Department of Agriculture Economic Research Service's Rural-Urban Continuum Codes, was categorized as "rural/urban/metropolitan." Multivariable logistic regression was used to examine rural-urban differences in palliative care use. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) were calculated.

Findings: Of 133,500 patients (mean age 62.4 [SD = 14.2] years), 86.7%, 11.7%, and 1.6% resided in metropolitan, urban, and rural areas, respectively; 72.5% were White, 17.0% Black, 5.8% Hispanic, and 2.7% Asian. Overall, 20.3% used palliative care, with a significant increase from 15.6% in 2004-2005 to 24.5% in 2008-2019 (7.0% increase per year; p-value for trend <0.001). In urban areas, 23.3% received palliative care, compared to 21.0% in rural and 19.9% in metropolitan areas (p < 0.001). After covariate adjustment, patients residing in rural (AOR = 0.84; 95% CI: 0.73-0.98) or metropolitan (AOR = 0.85, 95% CI: 0.80-0.89) areas had lower odds of having used palliative care than those in urban areas.

Conclusions: In this national, racially diverse sample of patients with metastatic breast cancer, the utilization of palliative care services increased over time, though remained suboptimal. Further, our findings highlight rural-urban disparities in palliative care use and suggest the potential need to promote these services while addressing geographic access inequities for this patient population.