A prospective evaluation of radiotherapy (RT) related skin reactions in a multi-racial/ethnic population of women with newly diagnosed breast cancer (BC).

6593 Background: RT-related early adverse skin reactions (EASR) are common in BC patients. EASR occur during/within 2 months post-RT. Predictive biomarkers for EASR are under active investigation. Previous studies have limited sample size/lack racial/ethnic diversity. This study designed to evaluate disparities in EASR of a multi-racial/ethnic BC population. Methods: Stage 0-III BC patients. Inclusion criteria: RT dose > 40 Gy and daily RT 1.8 to 2.7 Gy/fx. Regional nodal irradiation, mastectomy/lumpectopmy, concur/sequent boost, chemotherapy, hormonal therapy allowed. Exclusion criteria: immediate reconstruction, partial breast RT. Primary outcome: EASR (Oncology Nursing Society (ONS) acute skin toxicity (0-6 scale)) assessed during/2 months post-RT. Mixed effects repeated measures analysis of variance used to assess race/ethnicity and mastectomy/lumpectomy differences in EASR over time. Results: 10/2011-6/2013, 1000 patients accrued (405 non-Hispanic white (NHW), 277 non-Hispanic black (NHB), 241 Hispan...