288P - Impact of the 21-gene breast cancer assay on treatment recommendations for estrogen receptor-positive (ER+) early stage breast cancer (ESBC) in Hon...

Date 29 September 2014
Event ESMO 2014
Session Poster Display session
Topics Breast Cancer, Early Stage
Biomarkers
Diagnostics
Presenter Roland Leung
Citation Annals of Oncology (2014) 25 (suppl_4): iv85-iv109. 10.1093/annonc/mdu327
Authors R. Leung1, T. Yau2, C. Chao3, C. Yoshizawa3, P. Cheung4
  • 1Medicine, The University of Hong Kong, 999077 - Hong Kong/HK
  • 2Medicine, The University of Hong Kong, Hong Kong/HK
  • 3Medical Affairs, Genomic Health, Inc., Redwood City/US
  • 4Office Of The Founder, Hong Kong Breast Cancer Foundation, Hong Kong/HK

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 < 0.001 by McNemar's test). Pre-assay, 95% of physicians agreed (66%) or strongly agreed (29%) that they were confident in their treatment recommendation; post-assay, 91% of physicians agreed (51%) or strongly agreed (40%) with the same statement. Thirty percent of physicians agreed or strongly agreed that the test had influenced their recommendation, a number similar to the number of changed recommendations.

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.