-Original-

Predictors of Pathologically Negative Sentinel Lymph Nodes and Recurrence-Free Survival in Women with Invasive Breast Cancer Treated with Neoadjuvant Chemotherapy

Phanchaporn Wongmaneerung^1,2, Hiroyuki Takei³, Tomoko Kurita³, Meishi Hankyo³, Megumi Sano³, Keiko Yanagihara⁴, Takashi Sakatani⁵, Ryuji Ohashi⁵, Ryusuke Murakami⁶ and Shinichiro Kumita⁶

¹Division of Head, Neck and Breast, Department of Surgery, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
²Clinical Surgical Research Center, Chiang Mai University, Chiang Mai, Thailand
³Department of Breast Surgery and Oncology, Nippon Medical School Hospital, Tokyo, Japan
⁴Department of Breast Surgery and Oncology, Nippon Medical School Tama Nagayama Hospital, Tokyo, Japan
⁵Department of Diagnostic Pathology, Nippon Medical School Hospital, Tokyo, Japan
⁶Department of Radiology, Nippon Medical School Hospital, Tokyo, Japan

Background: The accuracy and safety of sentinel lymph node (SLN) dissection (SLND) have not been established for women with invasive breast cancer (BC) who underwent neoadjuvant chemotherapy (NAC). The purpose of this study was to identify factors that predict pathologically negative axillary lymph node (ALN) status and recurrence-free survival (RFS) in women with invasive BC and clinically negative ALN after NAC followed by SLND.
Methods: The analysis included patients with BC (T1-4, N0-1, M0) treated with NAC who had clinically negative ALNs after NAC followed by SLND between January 2018 and May 2022. Age, clinical tumor size, clinical ALN status, estrogen receptor (ER), progesterone receptor, human epidermal growth factor receptor 2 (HER2), molecular subtype, histological grade, Ki67, all at baseline, and pathologic tumor size after NAC were analyzed for correlations with pathological ALN metastasis and RFS.
Results: SLND identified at least one SLN (blue or radioactive node) in all of 112 consecutive patients. Multivariable analysis showed that age >50 years, clinically negative ALN, histologic grade II or III, ER negativity, triple negative subtype (all at baseline), and pathologically invasive tumor size of ≤2.0 cm after NAC showed a significant correlation with pathologically negative ALN. HER2 positivity and pathological complete response of the primary tumor were significantly correlated with favorable RFS.
Conclusions: These predictors of pathologically negative ALN and RFS after NAC are useful for planning appropriate surgical and adjuvant treatment for BC patients.

J Nippon Med Sch 2026; 93: 49-59

Keywords
breast cancer, neoadjuvant chemotherapy, axillary lymph node, sentinel lymph node dissection, recurrence-free survival

Correspondence to
Phanchaporn Wongmaneerung
Phanchaporn.w@cmu.ac.th

Received, April 8, 2025
Accepted, October 17, 2025