The impact of racial and socioeconomic disparities on radiation therapy delays in breast cancer patients: A National Cancer Database analysis.

Abstract

540 Background: Despite advancements in breast cancer (BC) treatment, significant disparities in outcomes persist in the United States. Timely initiation of adjuvant radiation therapy (RT) is crucial, as delays are associated with increased recurrence. Using the National Cancer Database (NCDB), this study provides a larger-scale analysis of racial and ethnic (R/E) disparities, examining the role of socioeconomic (SE) factors, including education and income, on RT delays and overall survival (OS) differences. Methods: A retrospective analysis was conducted using data from the NCDB. The study included female patients (pts) ≥18 years with stage I-III BC diagnosed between 2004 and 2020. Pts who received chemotherapy were excluded. Pts were categorized by R/E into four groups: White (W), Black (B), Hispanic (H), and Other (O). SE variables, including income and education, were stratified into quartiles (Q1–Q4) as defined by the NCDB. A delay in RT initiation was defined as starting treatment more than 3 months (mos) after surgery. Kaplan-Meier (KM) analysis with the log-rank test was used to compare OS across groups. Cox proportional hazards regression was performed to estimate hazard ratios (HR) and assess the impact of income and education on delays in RT and survival outcomes. Results: A total of 395,328 female BC pts were included in the analysis. The median age of the cohort was 65. Most were W (85.2%), followed by B (7.4%), H (4.0%), and O (3.5%). Almost all pts had stage I (81.6%) BC. The majority of patients were in the highest (Q4) income and education quartiles (40.2% and 45.6% respectively). Higher RT delays ( > 3 mos) were observed in B (11.07%) and H (11.38%) compared to W (5.31%), (p < 0.001). Pts in the lowest income and education quartiles (Q1) experienced delays more frequently (8.02% and 9.29%, respectively) compared to those in Q4 (5.72% and 5.27%, respectively p < 0.001). KM survival analysis revealed significant differences in OS for delayed RT, with median survival of 218 mos for 0–3 mos, 211 mos for 3–6 mos, and 209 mos for > 6 mos (p < 0.001). KM survival analysis also demonstrated worse survival for pts in Q1 income and education compared to Q4 (p < 0.001). Cox proportional hazards model, when adjusted for clinical, R/E and SE factors revealed that pts in Q1 for income (HR = 1.411, p < 0.001) and education (HR: 1.036, p < 0.001) had a significantly higher risk of mortality compared to Q4. Conclusions: This study highlights significant R/E and SE disparities in timely RT initiation and survival outcomes among BC pts. B, H, and pts with lower S/E status experienced greater RT delays, emphasizing the critical need for targeted interventions to address delays in care and improve equity in cancer treatment.