Usefulness of Breast MRI for Safe Omission of Axillary Lymph Nodes Dissection in Sentinel Node-Positive Breast Cancer Patients

Abstract

Background: Preoperative identification of patients with extensive lymph node metastasis (LNM) is important for safe omission of axillary lymph node dissection (ALND) in sentinel node (SN)-positive (SN+) breast cancer patients. Methods: We evaluated retrospectively the collected data of 758 breast cancer patients who underwent axillary surgery between 2008 and 2017, excluding those who received neoadjuvant chemotherapy. Results: Of the 758 patients, 607 were not suspicious to have LNM by axillary ultrasound (AUS-), but 38 suspicious cases were found by breast magnetic resonance imaging (MRI). Of 15 patients undergoing axillary fine needle biopsy (AFNA) due to second-look axillary ultrasound (AUS), 9 underwent ALND because of a positive AFNA (AFNA+). Among 81 (10.9%) patients undergoing ALND due to SN+ findings, 6 (7.4%) had extensive LNM (LNM ≥ 4). If MRI was not performed, among the 90 of 673 patients undergoing ALND who had SN+ findings, 12 (13.3%) had LNM ≥ 4. Conclusions: The proportion of cases with LNM ≥ 4 was reduced from 13.3% to 7.4% among patients undergoing SN biopsies combined with breast MRI. ALND might be omitted safely in SN+ cases according to detailed preoperative evaluations using additional breast MRI to ultrasound.