Adoption Of Hypofractionated Radiotherapy (Hyrt) For Ductal Carcinoma In Situ (Dcis): A Seer-Medicare Study.

1006 Background: Multiple randomized trials published in 2008-2010 demonstrated that for women with early-stage invasive breast cancer receiving adjuvant radiotherapy (RT) after a lumpectomy, shorter course (hypofractionated) RT is non-inferior to conventionally fractionated RT (CRT). However, the role of HyRT has not been evaluated prospectively for DCIS. The purpose of this study is to examine adoption of HyRT in DCIS. Methods: DCIS patients diagnosed from 2004-9 in the Surveillance Epidemiology and End Results (SEER)-Medicare database were included, with Medicare claims data available through 2010. A total of 4,459 women received lumpectomy followed by external beam RT. The number of RT treatments received by each patient was determined from Medicare claims, and grouped into: accelerated partial breast irradiation (APBI, ≤12 treatments), HyRT (13-24), or CRT (≥25). Proportions of women receiving different fractionation schemes were described per year of RT, and in subgroups based on patient and disease...