568^ Background: The 21-gene Oncotype DX Recurrence Score (RS) is a validated assay to help inform the appropriate treatment of estrogen receptor-positive (ER+), early stage breast cancer in the adjuvant setting. Treatment traditions regarding choice of adjuvant treatment vary significantly in different countries. This prospective multicenter study is the first to assess the impact of using the Oncotype DX assay in the French clinical setting. Methods: A total of 100 consecutive patients with ER+, HER2-negative, node negative or pN1 (mi) breast cancer were enrolled. Overall treatment recommendation change, change from chemoendocrine to endocrine alone and change from endocrine alone to chemoendocrine treatment were recorded. Medical oncologists completed questionnaires regarding their confidence in their recommendation before and after knowing the patient’s RS. A preliminary analysis was conducted on the first 92 evaluable patients with data available at the time of abstract submission. Final data will be presented at the meeting. Results: Prior to Oncotype DX 49% of patients were recommended chemoendocrine treatment and 51% endocrine treatment alone. After having the RS, 26% were recommended chemoendocrine treatment and 74% endocrine treatment alone. The overall reduction in chemotherapy recommendation from 49% to 26% was significant (p<0.001). Of patients originally recommended chemoendocrine treatment, 58% were changed to endocrine treatment alone after having the RS. Of patients originally recommended endocrine treatment, 11% were changed to chemoendocrine treatment after receiving the RS. There was a significant improvement in physician confidence in treatment recommendations (p=0.002) when using Oncotype DX. Conclusions: These are the first prospective data regarding the impact of using Oncotype DX in France. Using Oncotype DX was associated with a significant change in treatment decisions and an overall reduction in chemotherapy use. The data are consistent with those presented from Germany, Spain, the UK and the US.
Lifetime Cost-Effectiveness of Adjuvant External Beam Whole Breast Irradiation (EBWBI) in Estrogen Receptor Positive (ER+) Early-Stage Breast Cancer (ESBC) Women: Cardiotoxicity Consideration