The impact of intraoperative frozen section in patients with clinically node-negative breast cancer (cN0/ycN0) who received neoadjuvant systemic therapy.

BACKGROUND: When surgical axillary staging reveals residual metastatic deposits in breast cancer (BC) patients who had received neoadjuvant chemotherapy (NACT), axillary lymphonodectomy is indicated. In this study, we investigate whether it is reasonable to perform intraoperative frozen section (FS) of the removed sentinel lymph nodes (SLNs) in cases where NACT had been administered in patients who had a clinically negative nodal status at the time of diagnosis. PATIENTS AND METHODS: We analyzed data from 101 BCE patients with 103 carcinomas who were diagnosed between 2014 and 2021 and met the above-mentioned criteria. RESULTS: In three cases (2.8% of the study group), histologically active tumor tissue was detected in the removed axillary LNs. Discontinuation of therapy/the use of a low-dose NACT regimen was a significant factor for positive LNs (p = 0.02) at the subsequent surgical procedure; tumor progression during therapy approached borderline significance (p = 0.058). Among patients who had completed NACT with the planned standard dose regimen, and in which the primary tumors showed a response to therapy (n = 94), only one case had histologically detected residual metastases in the SLNs. CONCLUSIONS: Certified breast centers aim to improve the outcome of the patients. However, these specialized centers should also focus on economic aspects. This means that diagnostic and therapeutic procedures should be continuously critically reviewed in order to avoid unnecessary expenses. In BC patients with clinically node negative disease who completed NACT as planned and in which the tumor showed a good response to therapy, time consuming and costly FS of the SLNs removed should be omitted.