Multiple Step-section Frozen Section sentinel lymph node biopsy--a review of 717 patients.

Sentinel Lymph Node Biopsy (SLNB) is the standard of care for axillary staging in breast cancer. Multiple Step-section Frozen Section (MSFS) analysis is used in our institution for SLNB. This is performed intra-operatively by freezing sentinel lymph nodes to obtain multiple step-sections which are examined histologically for evidence of metastases. Patients whose sentinel lymph nodes contained macrometastases proceeded to an axillary node clearance during the same operation. 717 patients over a two and a half year period had MSFS analysis. With regards to macrometastases, MSFS analysis had a sensitivity of 93.8%, a specificity of 99.3%, a positive-predictive value of 97.4% and a negative-predictive value of 98.2%. MSFS analysis of sentinel lymph nodes is a safe and accurate procedure. It is a relatively cost-effective alternative to molecular technologies relying on DNA amplification and more accurate than standard frozen section or touch-prep cytology.