Association Between Travel Distance and Metastatic Disease at Diagnosis Among Patients With Colon Cancer

Abstract

Health care access and advanced cancer stage are associated with oncologic outcomes for numerous common cancers. However, the impact of patient travel distance to health care on stage at diagnosis has not been well characterized. This study used a historical cohort of patients with colon cancer in the National Cancer Data Base from 2003 through 2010. The primary outcome, stage at diagnosis, was evaluated using hierarchical regression modeling. A secondary outcome was time to receipt of initial therapy that was evaluated using Cox shared frailty modeling. Among 296,474 patients with colon cancer (mean age, 68 ± 13.6 years; 47.6% male; 78.5% white), 3.9% traveled ≥ 50 miles to the diagnosing facility. Fewer black patients, patients with higher income, and patients with lower education traveled longer distances (trend test P < .001 for all). Patients traveling ≥ 50 miles were more likely to present with metastatic disease compared with those traveling less than 12.5 miles (odds ratio [OR], 1.18; 95% CI, 1.12 to 1.24) or 12.5 to 49.9 miles (OR, 1.18; 95% CI, 1.12 to 1.24). In sensitivity analyses, the association was robust to alternate methods of modeling travel distance (quintile stratification or continuous). Travel distance ≥ 50 miles was also associated with a higher likelihood of earlier initiation of therapy compared with travel distance of less than 12.5 miles (hazard ratio [HR], 1.10; 95% CI, 1.08 to 1.13) or 12.5 to 49.9 miles (HR, 1.11; 95% CI, 1.08 to 1.13). Advanced colon cancer stage at diagnosis is associated with patient travel distance to health care, which may be a barrier to early cancer screening. Health care reform efforts designed to address only insurance coverage may not mitigate disparities based on difficulties accessing cancer care.