Uptake and Costs of Hypofractionated vs Conventional Whole Breast Irradiation After Breast Conserving Surgery in the United States, 2008–2013

IMPORTANCE Based on randomized evidence, expert guidelines in 2011 endorsed shorter, hypofractionated whole breast irradiation (WBI) for selected patients with early-stage breast cancer and permitted hypofractionatedWBI for other patients. OBJECTIVES To examine the uptake and costs of hypofractionatedWBI among commercially insured patients in the United States. DESIGN, SETTING, AND PARTICIPANTS Retrospective, observational cohort study, using administrative claims data from 14 commercial health care plans covering 7.4 % of US adult women in 2013, we classified patients with incident early-stage breast cancer treated with lumpectomy andWBI from 2008 and 2013 into 2 cohorts: (1) the hypofractionation-endorsed cohort (n = 8924) included patients aged 50 years or older without prior chemotherapy or axillary lymph node involvement and (2) the hypofractionation-permitted cohort (n = 6719) included patients younger than 50 years or those with prior chemotherapy or axillary lymph node involvement. EXPOSURES HypofractionatedWBI (3-5 weeks of treatment) vs conventional WBI (5-7 weeks of treatment)