Management of early stage HER2 positive breast cancer and increased implementation of axillary imaging to improve identification of nodal metastasis

• Published in: Journal of surgical oncology 2022-06, Vol.125 (8), p.1218-1223
• Main Authors: McCaffrey, Rachel L, Thompson, Jessica L, Oudsema, Rebecca H, Sciallis, Andrew P, Cobain, Erin F, Sabel, Michael S, Jeruss, Jacqueline S
• Format: Article
• Language: English
• Subjects: Axilla - pathology; axillary nodal management; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - therapy; early breast cancer; Female; HER2; Humans; Lymph Node Excision; Lymph Nodes - pathology; Lymphatic Metastasis - pathology; Lymphatic system; Neoadjuvant Therapy; Retrospective Studies; Sentinel Lymph Node Biopsy - methods
• ISSN: 0022-4790; 1096-9098
• DOI: 10.1002/jso.26840

Background and Objectives Given the significant benefit of targeted therapies for HER2+ breast cancer patients in both the neoadjuvant and adjuvant settings, it is critical to identify all eligible patients for these treatments. We sought to investigate cT1cN0 HER2+ patients to determine the rate of postsurgical nodal positivity, and to identify presurgical factors associated with nodal positivity. We hypothesize there is a subset of underdiagnosed HER2+ patients who would benefit from preoperative axillary imaging and inclusion in neoadjuvant chemotherapy regimens. Methods We performed a 10‐year retrospective analysis of T1 HER2+ breast cancer patients. Clinicopathologic characteristics were evaluated based on surgical nodal data. Results We identified 38 patients with cT1cN0 HER2+ cancer. Of this cohort, 24% had positive lymph nodes on final pathology. High tumor grade (p = 0.035) on core needle biopsy and the presence of lymphovascular invasion (p = 0.0036) were associated with an increased likelihood of lymph node positivity. The majority (66%) of lymph node positive patients were clinically T1c. Conclusions We identified a 24% nodal positivity rate in clinically node negative T1 HER2+ breast cancer patients. In particular, HER2+ patients with high‐grade T1c cancers should undergo preoperative diagnostic axillary imaging to expand potential benefit from targeted therapies.