Location as Destiny: Identifying Geospatial Disparities in Radiation Treatment Interruption by Neighborhood, Race, and Insurance.

BACKGROUND: Radiation therapy interruption (RTI) worsens cancer outcomes. Our purpose was to benchmark and map RTI across a **** region in the United States with known cancer outcome disparities. METHODS: All RT treatments at our academic center were cataloged. Major RTI was defined as >5 unscheduled RT appointment cancellations. Univariate and multivariable (MVA) logistic and linear regression analyses identified associated factors. Major RTI was mapped by patient residence. A two-sided p-value of 2 RT interruptions. 337 patients (9%) had major RTI. Disparities in major RTI were seen across Medicaid vs. commercial/Medicare insurance (22.5% vs. 7.2%, p=<0.0001), low vs. high predicted income (13.0% vs. 5.9%, p=<0.0001), Black vs. White race (12.0% vs. 6.6%, p=<0.0001), and urban vs. suburban treatment location (12.0 vs. 6.3%, p=<0.0001). On MVA, increased odds of major RTI were seen for Medicaid patients (OR 3.35 95%CI 2.25-5.00, p=<0.0001; v commercial/Medicare), and head & neck (OR 3.74 95% CI 2.56-5.46, p=<0.0001), gynecologic (OR 3.28 95%CI 2.09-5.15, p=<0.0001), and lung cancers (OR 3.12 95%CI 1.96-4.97, p=<0.0001) compared to breast cancer. Major RTI mapped to urban, majority Black, low-income neighborhoods, as well as to rural, majority White, low-income regions. CONCLUSION: Radiation treatment interruption disproportionately impacted financially and socially vulnerable patient populations and mapped to high poverty neighborhoods. Geospatial mapping affords an opportunity to correlate RT access on a neighborhood level to inform potential intervention strategies.