Intraoperative Sentinel Node Fine-Needle Aspiration Biopsy as a Substitute for Whole Sentinel Node Excisional Biopsy in Breast Cancer Patients. Initial Report

Introduction: Sentinel Node Biopsy (SNB) is the choice procedure for axillary staging in Breast Cancer. Following the ACOSOG Z11 trial, axillary dissection is advised only in patients with more than 2 positive SNs. We aimed at exploring palpation-guided, intraoperative fine-needle aspiration biopsy of the SN as a replacement for whole SN excision in node-negative BC patients to minimize side-effects.

Patients and methods: We included 80 patients with BC undergoing SNB between December 2020 and May 2022. After identification of the SN, the breast surgeon performed SN-FNAB. Results were compared with definitive pathological assessment. ResultsDiagnostic yield was 80%, including a "learning curve." 58 of 64 patients with suitable samples tested negative. In this group, the Negative Predictive Value was 77.6% (IC 64.7%-87.5 %). If micro metastasis is disregarded, the NPV would increase to 86.2% (IC 74.6%-93.9%). If we accept the Z11 criterion for axillary dissection, the NPV would rise to 100%. Six patients had a positive SN-FNAB. They were all confirmed as having macro metastatic-positive SNs at the final pathological assessment, and 3 of them also displayed extra nodal extension (ENE).

Conclusion: We believe that intraoperative SN-FNAB is highly accurate for swiftly depicting both low axillary tumor burden/negative cases, in whom axillary dissection is to be omitted, as well as high axillary tumor burden cases.