The accuracy of intraoperative frozen section analysis of the sentinel lymph nodes during breast cancer surgery

Background-The sentinel node biopsy (SNB) is a reliable and minimally invasive procedure, representing a new standard of care for patients with clinically node-negative breast cancer. Several studies have confirmed the reliability and the accuracy of this new procedure. Accurate intraoperative evaluation of sentinel lymph nodes (SLNs) can determine the need for immediate axillary node clearance thus reducing arm morbidity in SLN-negative patients and avoiding a second surgical procedure in patients with positive SLNs. The aim of this study is to determine the accuracy and the limitations of intraoperative frozen section (IFS) analysis of SLNs during breast cancer surgery. Patients and Methods-96 female patients with clinically node-negative T1-T2 breast cancer who underwent the SNB procedure and IFS analysis by single section standard staining in two hospitals were reviewed. The SNB procedure was performed using the patent blue dye method alone or the combination of the dye and radioactive isotope techniques. The results of IFS and the final histology were compared. Results-The mean number of SLNs removed was 2. Overall, 22% (21/96) of patients were found to be SNB-positive on final histology. Based on patients, there was a 96.8% concordance between the results of the IFS and the final histology; the sensitivity was 86% (18/21), and the specificity was 100%. There were 3 cases of false negative all of which contained micrometastases only. When micrometastases were excluded, the sensitivity was 100%. Based on SLNs (n = 196), the sensitivity was 91%, and the specificity was 100%. Conclusion-Intraoperative frozen section of sentinel lymph nodes in patients with early breast cancer is highly accurate for macrometastases but not for micrometastases.