288P - Impact of the 21-Gene Breast Cancer Assay on Treatment Recommendations for Estrogen Receptor-Positive (Er+) Early Stage Breast Cancer (Esbc) in Hong Kong

Abstract

ABSTRACT Aim: The 21-gene breast cancer assay has been validated to assess risk of distant recurrence and the likelihood of chemotherapy (CT) benefit in ER+ ESBC patients in a number of different populations. In Hong Kong >80% of breast cancers are ESBC and >60% of these women receive CT. The assay's impact on adjuvant treatment recommendations has not been reported in a Chinese population. This prospective decision impact study measured changes in physician treatment recommendations in this new population of patients. Methods: Eligible patients from 6 institutions had ER + , T1-3 N0-1mi M0 ESBC. After surgery, physicians discussed treatment options with patients, then ordered the assay. After receipt of the result the treatment recommendation was reassessed. Changes in treatment recommendation, CT utilization, and physician confidence were measured, as was physician rating of influence on their recommendation. Results: One hundred fifty consecutive patients were enrolled. Four were not evaluable. The remaining 146 eligible patients had treatment recommendations before and after testing. CT recommendations, which included changes in CT intensity, were changed for 34/146 patients, (23.3%, 95% CI 16.7%-31.0%). There were 27 changes in treatment recommendations of adding or removing CT altogether (18.5% change, 95% CI 12.6%-25.8%). CT recommendations decreased from 52.1% to 37.7%, a net reduction of 14.4% (p Conclusions: The primary outcome suggests that the 21-gene breast cancer assay influences adjuvant treatment recommendations by physicians in Hong Kong for their patients with ESBC. Disclosure: R. Leung, T. Yau and P. Cheung:: We received financial support from Genomic Health, Inc. for the conduct of this study. I have no other conflicts of interest to declare; C. Chao: I am an employee and hold stock shares in Genomic Health which develops and commercializes the Oncotype DX assay; C. Yoshizawa: I am an employee and hold stock shares in Genomic Health which develops and commercializes the Oncotype DX assay.