Abstract P6-17-36: Consensus and disagreement among experts for treatment of patients with HER2+ early-stage breast cancer suggests unmet need for online decision support tool
Authors: Holmes FA , Rosenthal KM , Hurvitz S , Pegram MD , Yardley DA , Obholz KL , O'Shaughnessy J 
Published: May 2019

Abstract
Treatment (tx) choices for HER2+ early stage breast cancer (EBC) have become increasingly complex. Clinicians and patients must decide 1) which chemotherapy and HER2-targeted agents to use, 2) the sequence of surgery and chemotherapy: either neoadjuvant (neoadj) or adjuvant (adj) tx, and 3) whether to shorten or extend maintenance HER2-targeted tx.
As tx options expand, so does the need for online decision aids. One online decision support tool was developed in 2015 to provide specific tx recommendations for pts with EBC and showed that community healthcare providers (HCPs) did not consistently align with experts for neoadj or adj tx of many pts with EBC (SABCS 2015 Abs P5-09-04).
This study includes analysis of neoadj and adj tx practice patterns of 5 breast cancer experts based on their tx recommendations for 270 unique HER2+ EBC case scenarios made for development of a 2018 online decision tool. We aim to compare these recommendations with the intended treatment of clinicians using the tool.
Results
Experts agree on neoadj tx approaches: initial surgery, no neoadj tx for pts with cT1a/b N0 tumors; neoadj tx before surgery for pts with ≥cT2 or N+ tumors. There was disparity among experts for pts with cT1c N0 disease: 3 experts recommend neoadj TCH±P and 2 recommend proceeding directly to surgery.
Experts generally recommend adj TCHP for pts with stage II N+ or higher HER2+ EBC who did not receive neoadj tx. In addition, 5/5 experts would consider extended adj tx with neratinib for these pts if HR+ and 2/5 experts would also consider neratinib if HR–.
In pts who received neoadj chemo+HER2 tx, post-surgery management depends on response to neoadj tx. For pts with pCR, 5/5 experts generally agree on continuing H+P if both were given as neoadj tx or H alone if only H given as neoadj tx for a total of 1 yr of anti-HER2 Ab tx and 2/5 experts would consider extended adj tx with neratinib for HR+ disease. For pts with residual disease, experts would recommend continuing H+P if both were given as neoadj tx and most would add P for subsequent adj tx if H alone was given to complete a total of 1 yr of anti-HER2 Ab tx (Table1). All experts would consider extended adj tx with neratinib for HR+ disease and 3/5 experts would also consider neratinib for HR– disease. None of the experts recommended less than 12 mos of adj HER2-targeted tx.
We will present analyses of cases entered into our online tool and detailed comparisons of expert and the intended treatment of clinicians using the tool.
Conclusions
Practice patterns are changing rapidly and are more complex in response to the evolving treatment landscape for HER2+ EBC. This analysis highlights several areas of expert consensus; however, disparities remain for select cases. The current tool addresses an unmet medical need for expert-led evaluation of HER2+ EBC tx choices and warrants further investigation.
Expert Recommendations: Initial Adj HER2 Ab Tx After Neodj Tx With H Alone ExpertsResponse12345pCR (HR-)HHHHHpCR (HR+)HHHHHypT1a-c N0 (HR-)H + PHH + PH + PH + PypT1a-c N0 (HR+)H + PHHH + PHypT2 N0 (HR-)H + PH + PH + PH + PH + PypT2 N0 (HR+)H + PH + PHH + PH + PypTany N+ (HR+ or HR-)H + PH + PH + PH + PH + P
Citation Format: Holmes FA, Rosenthal KM, Hurvitz S, Pegram MD, Yardley DA, Obholz KL, O'Shaughnessy J. Consensus and disagreement among experts for treatment of patients with HER2+ early-stage breast cancer suggests unmet need for online decision support tool [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-36.