Impact of radiation therapy facility volume on survival in patients with cancer

Abstract

Background: This study examined whether radiation therapy facility volumes correlate with survival after curative intent treatment of solid tumors. Methods: The National Cancer Database was queried for patients with solid tumors treated with curative-intent radiation therapy from 2004-2013. Facilities were stratified into 4 volume categories: low, intermediate, high, and very high. Primary cancer sites were divided into neoadjuvant, adjuvant, or definitive radiation subgroups. Kaplan-Meier curves of 5-year postradiation survival probability, stratified by facility volume, were generated with log-rank tests for group comparisons. Cox proportional hazard models were used to evaluate the effect of facility volume on survival, adjusted for multiple covariates. Results: There were 253,422 patients treated at 1289 facilities: 6231 received neoadjuvant radiation, 147,980 received adjuvant radiation, and 99,211 received definitive radiation without surgery. Among patients receiving neoadjuvant radiation, survival correlated with facility volume for patients with rectal cancer (hazard ratio [HR], 0.75; 95% CI, 0.6-0.94; P =.01). For cancers of the breast and uterus, patients receiving adjuvant radiation at very high-volume facilities (vs low volume) had improved survival (HR, 0.83; 95% CI, 0.77-0.90; P