Intraoperative Assessment of Sentinel Lymph Nodes in Breast Cancer Patients Post-Neoadjuvant Therapy

Abstract

Background:Shift toward minimizing axillary lymph node dissection in patients with breast cancer post neoadjuvant therapy has led to the assessment of sentinel lymph nodes by frozen section intraoperatively to determine the need for axillary lymph node dissection. However, few studies have examined the accuracy of sentinel lymph node frozen section after neoadjuvant therapy. Our objective is to compare the accuracy of sentinel lymph node frozen section in patients with breast cancer with and without neoadjuvant therapy and to identify features that may influence accuracy.Design:We identified 161 sentinel lymph node frozen section from 77 neoadjuvant therapy patients and 255 sentinel lymph node frozen section from 88 non-neoadjuvant therapy patients diagnosed between 2010 and 2016 in 2 institutions. The frozen section diagnoses were compared to the final diagnoses, and clinicopathologic data were analyzed.Results:The sensitivity, specificity, and accuracy of frozen section analysis were comparable between neoadjuvant therapy patients and non-neoadjuvant therapy patients (71.9% vs 50%, 100% vs 100%, and 88.3% vs 81.8%). Nine (11.7%) of 77 neoadjuvant therapy patients had discordant results, most often due to undersampling (tumor absent on frozen section slide). Four of these patients subsequently underwent axillary lymph node dissection. Discordant results (all false negatives) were significantly more likely in neoadjuvant therapy patients with Estrogen Receptor-positive/HER2-negative status, and in sentinel lymph node with pN1mic and pN0i+ deposits; age, preneoadjuvant therapy lymph node status, histotype, nuclear grade, tumor size, and response to neoadjuvant therapy showed no significant differences. For non-neoadjuvant therapy cases, large tumor size, lobular histotype, and sentinel lymph node with pN1mic and pN0i+ were associated with false-negative frozen section assessment.Conclusion:Sentinel lymph node frozen section diagnosis post-neoadjuvant therapy has comparable sensitivity, specificity, and accuracy to the sentinel lymph node frozen section diagnosis in the non-neoadjuvant therapy setting.

Challenges and Clinical Relevance of Modern Breast Pathology Reporting: Your Questions Answered

“…The most consistent factors associated with falsenegative results are the presence of a small volume of metastasis, micrometastasis, and isolated tumour cells [90,91]. Wong et al [90] noted a reduction in the falsenegative rate from 28.1% to 20.7% when cases displaying isolated tumour cells in SLNs were excluded.…”

“…While frozen section analysis is regarded as accurate for margin and sentinel node assessment [84,85], data on its accuracy in the post-neoadjuvant setting are relatively scant. Investigations on intraoperative frozen section analysis of sentinel lymph node biopsy (SLNB) in breast cancer cases following neoadjuvant chemotherapy have demonstrated comparable sensitivity, specificity, and accuracy when compared to nonneoadjuvant cohorts [86][87][88][89][90]. Despite the high overall accuracy in the post-neoadjuvant setting, ranging from 80 to 90% [86][87][88][89][90], there exists a considerable false-negative rate in the intraoperative assessment of SLNs in node-positive, neoadjuvant-treated breast cancer cases, reported to be between 5 and 40% [90][91][92][93].…”

Risk factors of non-sentinel lymph node metastasis in breast cancer with 1–2 sentinel lymph node macrometastases underwent total mastectomy: a case-control study

“…With the application of sentinel lymph node biopsy (SLNB) and its support by safety studies, the surgical management of the axillary in breast cancer patients has undergone significant changes [ 2 ]. For patients with preoperative cN+, ALND is still recommended.…”

Risk factors of non-sentinel lymph node metastasis in breast cancer with 1–2 sentinel lymph node micrometastases: a case control study

“…With the application of sentinel lymph node biopsy (SLNB) and the support of its safety studies, the surgical management of the axillary in breast cancer patients has undergone major changes [2]. For patients with cN + before surgery, ALND is still recommended.…”