Frozen section in axillary sentinel lymph nodes for diagnosis of breast cancer micrometastasis.

BACKGROUND Sentinel lymph node (SLN) biopsy plays a major role in the surgical management of primary breast cancer. The aim of this study was to assess the diagnostic accuracy of the assessment of axillary frozen sections of SLNs for micrometastasis diagnosis. PATIENTS AND METHODS This study focused on 278 SLNs from 149 patients. Each lymph node was fully analyzed by frozen section. After fixation, serial sections were cut and stained by hematoxylin and eosin (HE) and for pan-cytokeratins by immunohistochemistry (IHC). RESULTS Tumor cells were detected in 63 SLNs, 41 on frozen sections and 22 on controls. Of these 63 positive SLNs, 42 contained metastases, 10 contained micrometastases and 11 contained isolated tumor cells. The specificity and positive predictive value of SLN frozen sections for micrometastasis was 100%. The sensitivity was 83.3% for metastasis, 40% for micrometastasis; the false-negative rate was 16.7% for metastasis and 60% for micrometastasis. CONCLUSION Analysis of frozen section of SLNs is an accurate method for metastasis detection, allowing concurrent axillary dissection when positive. The protocol for SLN analyses described herein shows good sensitivity for micrometastasis detection.