Abstract
INTRODUCTION: Timely treatment initiation is critical to clinical outcomes in breast cancer (BC). While social determinants of health are established drivers of disparities in the timeliness of care (ToC), the impact of travel burden remains less defined. This study evaluates associations between travel burden, ToC, and overall survival (OS) in a nationally representative BC cohort. METHODS: We analyzed 283,166 BC patients from the National Cancer Database (2004-2021) with documented great circle distance (GCD), categorized as ≤ 10, 10.1-20.0, and > 20 miles. Associations between GCD and ToC-defined as time from diagnosis to first treatment and categorized as < 8, 8-12, and > 12 weeks-were assessed using negative binomial models, and associations with OS were evaluated using Cox models. RESULTS: Compared to patients with GCD < 10 miles, patients with GCD > 20 miles experienced delays in ToC when diagnosed with early-stage disease, especially when undergoing surgery as first treatment (RR: 1.05, 95% CI: 1.04-1.06). Compared to treatment within 8 weeks of diagnosis, treatment initiation > 12 weeks had 24% higher mortality (HR: 1.24, 95% CI: 1.14-1.35), especially among patients receiving surgery (HR: 1.31, 95% CI: 1.19-1.43) and chemotherapy (HR: 1.30, 95% CI: 1.18-1.43). Even surgery within 8-12 weeks carried an elevated risk (HR: 1.09, 95% CI: 1.02-1.16). Metropolitan patients with GCD > 20 miles had a 12% lower mortality (HR: 0.88, 95% CI: 0.81-0.96) than those ≤ 10 miles away; no such differences were observed in urban or rural groups. CONCLUSION: Travel burden influences BC ToC and OS through geographic, clinical, and facility factors, underscoring the need for tailored interventions that address local care capacity, patient demographics, and disease profiles.