Improved Axillary Staging of Breast Cancer with Sentinel Lymphadenectomy

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Abstract
The authors evaluated the effect of intraoperative lymphatic mapping and sentinel lymphadenectomy (SLND) on the axillary staging of patients with carcinoma of the breast. The accurate staging of patients with breast cancer is essential to guide management and determine prognosis. The authors previously reported the feasibility and accuracy of SLND in breast carcinoma. Sentinel lymphadenectomy identifies the first (“sentinel”) axillary lymph node draining the site of a primary tumor; because this node is the most likely site of axillary metastasis, histopathologic examination of the sentinel node correlates well with examination of the entire axillary contents. The current study compares SLND with standard axillary lymphadenectomy (ALND) for the staging of breast carcinoma. The incidence of axillary node metastasis and micrometastasis in SLND and ALND specimens from patients undergoing operative treatment of a primary breast carcinoma was compared prospectively. Multiple sections of each sentinel lymph node in SLND specimens were examined by hematoxylin and eosin (H&E) staining and by immunohistochemical techniques using antibodies to cytokeratin. One or two sections of each nonsentinel lymph node in ALND specimens were examined by routine H&E staining. One hundred thirty-four patients underwent ALND (ALND group), and 162 underwent successful SLND followed by completion ALND (SLND group). Both groups were similar with respect to age (median, 55 and 54 years, respectively), palpable primary tumors (54.5% and 59.3%, respectively), palpable axillary nodes (5.2% and 7.4%, respectively), size of primary tumor (median, 1.5 cm in each group), and total number of axillary lymph nodes examined (median, 19 and 21, respectively). The number of patients with axillary metastasis was 39 (29.1%) in the ALND group and 68 (42.0%) in the SLND group (p < 0.03). Of these, 4 of 39 (10.3%) ALND patients (3.0% of all ALND patients) and 26 of 68 (38.2%) SLND patients (16.0% of all SLND patients) had micrometastasis (≤2 mm), a highly significant difference (p < 0.0005)