Effect of distance to radiation treatment facility on use of radiation therapy after mastectomy in elderly women

Abstract

We sought to study the effect of distance to the nearest radiation treatment facility on the use of postmastectomy radiation therapy (PMRT) in elderly women. Using data from the linked Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database, we analyzed 19,787 women with Stage I or II breast cancer who received mastectomy as definitive surgery during 1991 to 1999. Multivariable logistic regression was used to investigate the association of distance with receipt of PMRT after adjusting for clinical and sociodemographic factors. Overall 2,075 patients (10.5%) treated with mastectomy received PMRT. In addition to cancer and patient characteristics, in our primary analysis, increasing distance to the nearest radiation treatment facility was independently associated with a decreased likelihood of receiving PMRT (OR = 0.996 per additional mile, p = 0.01). Secondary analyses revealed that the decline in PMRT use appeared at distances of more than 25 miles and was statistically significant for those patients living more than 75 miles from the nearest radiation facility (odds of receiving PMRT of 0.58 [95% CI = 0.34-0.99] vs. living within 25 miles of such a facility). The effect of distance on PMRT appeared to be more pronounced with increasing patient age (>75 years). Variation in the effect of distance on radiation use between regions of the country and nodal status was also identified. Oncologists must be cognizant of the potential barrier to quality care that is posed by travel distance, especially for elderly patients; and policy makers should consider this fact in resource allocation decisions about radiation treatment centers.