Abstract P2-14-22: Is sentinel lymph node biopsy necessary in breast cancer patients who were diagnosed as initially clinically node-negative before neoadjuvant chemotherapy?
Authors: Fujita T , Sakuragi M , Miyazaki C , Shiba S , Tanaka Y , Nishida S 
Published: May 2019

Abstract
Background
Neoadjuvant chemotherapy (NAC) is established for treatment of locally advanced disease and is being used increasingly for early-stage breast cancer. And sentinel lymph node biopsy (SLNB) for clinically node-negative breast cancer patients after NAC is performed as a daily procedure. The purpose of this study was to identify the group that can omit SLNB in patients with clinically node-negative breast cancer at diagnosis before NAC.
Materials and Methods
A single institutional retrospective analysis was performed. 126 patients were diagnosed as clinically node-negative before NAC and underwent SLNB between 2005 and 2017.
Before NAC, all patients underwent clinical assessment of lymph-node status by palpation and axillary ultrasound. We judged patients to be node-negative when palpation and ultrasound showed no suspicious nodes. If axillar lymph nodes were swelling, fine-needle aspiration cytology was performed. After NAC, clinical assessment of lymph-node status was performed, again.
119 patients received anthracycline-based (anthracycline alone: 11, anthracycline followed by taxane: 108) chemotherapy and 7 patients received taxane alone. Clinical complete response (cCR) was defined if there was no evidence of tumor in the breast and axillary lymph nodes by US and MRI. SLNB procedure was done after NAC in all patients. Lymphatic mapping was performed with radioactive colloid and/or lymphatic blue dye.
Results
Median follow-up time was 51.2months. cCR rate was 16.7% (21/126).
Success rate for the identification and removal of a SLN was 96.8% (122/126). The median number of SLNs removed was 1.9 (1-5).
15 patients (12.3%) represented SLN positive in patients who were diagnosed as clinically node-negative before NAC. They were performed axillar dissection and the SLNs were the only positive nodes in 9 patients.
No SLNs metastases were observed in 21 patients who were diagnosed as cCR by ultrasound and MRI. And 15 patients (14.9%) had positive SLN in the 101 patients who were diagnosed as clinical partial response or clinical stable disease (p=0.071).
Tumor size, Surgical procedures, hormone receptor status and HER2 status did not influence the positive rate of SLN metastases.
No axillar lymph node recurrence was observed within follow-up period.
Conclusion
Our results show that SLNB is necessary even in breast cancer patients who were diagnosed as initially clinically node-negative before NAC.
However, SLNB may be omitted in breast cancer patients who were diagnosed as clinically node-negative by palpation and axillary ultrasound before NAC and as cCR by ultrasound and MRI after NAC.
Citation Format: Fujita T, Sakuragi M, Miyazaki C, Shiba S, Tanaka Y, Nishida S. Is sentinel lymph node biopsy necessary in breast cancer patients who were diagnosed as initially clinically node-negative before neoadjuvant chemotherapy? [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 P2-14-22.