Intraoperative Assessment of Sentinel Lymph Nodes After Neoadjuvant Chemotherapy in Patients with Breast Cancer

Sentinel lymph node (SLN) biopsy has been shown to be both accurate and feasible for women who receive neoadjuvant chemotherapy (NAC). This study was designed to evaluate the ability of intraoperative assessment to predict metastasis in the sentinel node after NAC and to compare it with patients not treated with NAC. Thirty-seven patients with invasive breast cancer and SLN biopsy after NAC and 461 patients with invasive breast cancer not treated with NAC were included in the study. The SLN was identified by the gamma probe and sent to pathology for frozen (FS) and H&E paraffin-sections. If the SLN was negative by H&E paraffin-sections, then immunohistochemistry was performed. The sensitivity of FS in the NAC group ranged from 78.5% for micro and isolated tumor cells to 100% for macrometastasis. The sensitivity of FS in the non-NAC group ranged from 82% for micro and isolated tumor cells to 97.4% for macrometastasis. There were no statistically differences between the sensitivities of FS in the two groups. Nine (64.2%) of the 14 patients in the NAC group with metastasis to the SLN had other non-SLN metastasis. After NAC, FS is an effective method for detecting macrometastasis in the SLN. As in the adjuvant setting, the sensitivity of FS is lower for SLN micro and sub-micrometastasis. Intraoperative FS of the SLN after NAC is indicated to avoid a second surgery because 60% of patients with a positive SLN will have additional positive axillary nodes.