Abstract P1-14-20: HER2 and estrogen receptor status drive decisions regarding the use of neoadjuvant chemotherapy
Authors: Love N , Blackwell KL , Mamounas EP , Moss J , Ziel K 
Published: May 2016

Background: Neoadjuvant chemotherapy (NC) is widely utilized to facilitate breast-conserving surgery and is considered equivalent to adjuvant chemotherapy with regard to recurrence-free and overall survival. However, controversy exists about specific indications for NC and its effects on other outcomes, particularly related to surgery in the breast and axilla. Limited data are available about specific recommendations of breast cancer-focused clinical investigators (CI).

Methods: A 139-item survey was sent in May 2015 to 94 US-based surgical (S) and medical oncology (MO) CI from a proprietary database to assess their usual practice patterns. A modest honorarium was provided.

Results: The assessment was completed by 59 CI (28 S and 31 MO; 63% of those sent the survey). Most (86%) recommend NC to patients with estrogen receptor-negative/HER2-negative (ER-/HER2-) and HER2-positive (HER2+) tumors larger than 2 cm or with biopsy-proven axillary node involvement. For such patients with HER2+ tumors, MO routinely (98%) use pertuzumab (P) with trastuzumab (T) combined with NC — either paclitaxel (14%), docetaxel (7%), docetaxel/carboplatin (55%) or a taxane and doxorubicin (24%). For patients with these higher-risk HER2+ tumors not receiving NC, 52% of MO use P in the adjuvant setting, either during chemotherapy or continuing for a year. There was more heterogeneity and less use of NC in patients with ER-positive (ER+)/HER2- tumors, and 48% of MO use genomic profiling (generally the 21-gene Recurrence Score® to facilitate this decision. Globally, for the 36 defined scenarios that were evaluated, S were somewhat more likely to recommend NC (70%) than MO (63%). In terms of axillary management, S typically employ post-NC sentinel node biopsy (SNB; 82%) and only proceed to axillary dissection if the SNB is positive.

Conclusions: S and MO CI consider ER and HER2 (with tumor size and axillary node status) essential factors in NC decisions. In 2013, P (in combination with NC/T) became the first agent to receive FDA approval in the neoadjuvant setting in patients with HER2+ tumors, and it is now commonly used in both the adjuvant and neoadjuvant settings. The algorithms generated by this assessment will be helpful in educating community-based physicians, and as a result an online point-of-care tool to facilitate these decisions is being developed and evaluated.

  Neodajuvant chemotherapy? (%)*Nodal statusTumor size (cm)ER-/HER2+ER+/HER2+ER-/HER2-**ER+/HER2-Biopsy positive: Palpable1.0-2.0Yes: 86Yes: 81Yes: 80Yes: 24No: 7No: 8No: 7No: 39G: 24 2.1-3.0Yes: 93Yes: 92Yes: 88Yes: 36No: 2No: 5No: 5No: 25G: 29 3.1-5.0Yes: 100Yes: 98Yes: 95Yes: 49No: 0No: 2No: 2No: 7G: 29Biopsy positive: Imaging1.0-2.0Yes: 71Yes: 73Yes: 64Yes: 10No: 10No: 12No: 7No: 46G: 27 2.1-3.0Yes: 88Yes: 88Yes: 83Yes: 17No: 2No: 7No: 5No: 29G: 34 3.1-5.0Yes: 98Yes: 98Yes: 93Yes: 37No: 0No: 2No: 2No: 8G: 32Clinically negative1.0-2.0Yes: 22Yes: 15Yes: 20Yes: 2No: 51No: 63No: 46No: 54G: 39 2.1-3.0Yes: 69Yes: 66Yes: 71Yes: 5No: 12No: 17No: 17No: 42G: 46 3.1-5.0Yes: 92Yes: 92Yes: 85Yes: 15No: 3No: 2No: 5No: 15G: 49* Remaining responses = no preference between neoadjuvant and adjuvant chemotherapy; ** BRCA-negative; G = genomic assay ordered

Citation Format: Love N, Blackwell KL, Mamounas EP, Moss J, Ziel K. HER2 and estrogen receptor status drive decisions regarding the use of neoadjuvant chemotherapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-14-20.