The importance of pre-operative axillary ultra-sound and intra-operative sentinel lymph node frozen section analysis in patients with early breast cancer--a 3-year study.

Background: To ensure appropriate axillary surgery is performed at a single operation, we have sought to identify patients with involved nodes who might progress directly to axillary dissection.

Methods: We evaluated pre-operative ultrasound of the axilla and intra-operative frozen section of sentinel lymph nodes over a 3-year period. Patients with clinical early breast cancer underwent axillary ultrasound. Abnormal nodes were defined as a cortex > 2.5 mm, loss of high echogenic medulla, and morphological changes. Any axilla containing a lymph node considered abnormal had ultrasound-directed fine needle aspiration (FNA) performed. Patients with positive cytology proceeded directly to axillary dissection. Patients with negative cytology and those with normal ultrasound proceeded to sentinel four-node biopsy using Patent Blue dye alone. A single sentinel node was evaluated by intra-operative frozen section.

Results: A total of 311 patients underwent pre-operative ultrasound successfully, identifying 115 (77%) patients of the total 150 who were found to have positive lymph nodes. Overall, 196 patients underwent sentinel lymph node biopsy analysis intra-operatively. Of the 11 false negative cases in which the lymph node was found to be positive postoperatively, eight cases showed the single tested sentinel node contained cancer that was recognised on postoperative staining but not frozen section. In six, the deposit in the sentinel node was a micrometastasis. Three cases were found to contain cancer in the 'non-sentinel' node; in all, this was micrometastatic disease.

Conclusions: This study confirms the value of pre-operative ultrasound and intra-operative frozen section examination of axillary nodes. Only 3.5% of patients required two operations.