Preoperative axillary ultrasound in breast cancer: safely avoiding frozen section of sentinel lymph nodes in breast-conserving surgery.

BACKGROUND: The American College of Surgeons Oncology Group Z0011 trial results provided convincing evidence that completion axillary lymph node dissection (CALND) was unnecessary in selected patients with 1 to 2 positive sentinel lymph nodes (SLNs). We hypothesized that preoperative axillary ultrasound (AUS) with fine-needle aspiration is sufficiently sensitive to detect worrisome macrometastasis to preclude the need for frozen-section pathology of SLNs. STUDY
DESIGN: We conducted a retrospective single-institution study at a tertiary academic referral center. A total of 1,140 T1 to 2 breast cancer patients who underwent SLN biopsy with or without CALND from January 1, 2007 to December 31, 2010 were reviewed. All patients had negative preoperative AUS with or without fine-needle aspiration.
RESULTS: One hundred forty-four (13%) patients were node positive at surgery. Mean age, tumor size, histology, and estrogen receptor and progesterone receptor status were similar comparing 996 SLN-negative with 144 (13%) SLN-positive patients. Of the SLN-positive patients, 25% were premenopausal, 9% were estrogen receptor-negative, and 19% had additional lymph nodes at CALND. Only 19 (2%) patients had SLN metastasis ≥6 mm, 10 (1%) had metastasis >7 mm, and only 1 patient had ≥3 positive SLNs.
CONCLUSIONS: The addition of preoperative AUS with or without fine-needle aspiration to management of patients who meet American College of Surgeons Oncology Group Z0011 trial eligibility criteria reduced the risk of macrometastasis measuring ≥6 mm to only 2%; very few of these patients would be premenopausal, have estrogen receptor-negative tumors, or ≥3 positive SLNs. With the addition of AUS with or without fine-needle aspiration, we endorse the conclusions of the American College of Surgeons Oncology Group Z0011 trial to avoid CALND, and see marginal gain in frozen-section analysis of SLNs.