IMPROVED AXILLARY STAGING OF BREAST-CANCER WITH SENTINEL LYMPHADENECTOMY

Objective The authors evaluated the effect of intraoperative lymphatic mapping and sentinel lymphadenectomy (SLND) on the axillary staging o f patients with carcinoma of the breast. Summary Background Data The a ccurate staging of patients with breast cancer is essential to guide m anagement and determine prognosis. The authors previously reported the feasibility and accuracy of SLND in breast carcinoma. Sentinel lympha denectomy identifies the first (''sentinel'') axillary lymph node drai ning the site of a primary tumor; because this node is the most likely site of axillary metastasis, histopathologic examination of the senti nel node correlates well with examination of the entire axillary conte nts. The current study compares SLND with standard axillary lymphadene ctomy (ALND) for the staging of breast carcinoma. Methods The incidenc e of axillary node metastasis and micrometastasis in SLND and ALND spe cimens from patients undergoing operative treatment of a primary breas t carcinoma was compared prospectively. Multiple sections of each sent inel lymph node in SLND specimens were examined by hematoxylin and eos in (H&E) staining and by immunohistochemical techniques using antibodi es to cytokeratin. One or two sections of each nonsentinel lymph node in ALND specimens were examined by routine H&E staining. Results One h undred thirty-four patients underwent ALND (ALND group), and 162 under went successful SLND followed by completion ALND (SLND group). Both gr oups were similar with respect to age (median, 55 and 54 years, respec tively), palpable primary tumors (54.5% and 59.3%, respectively), palp able axillary nodes (5.2% and 7.4%, respectively), size of primary tum or (median, 1.5 cm in each group), and total number of axillary lymph nodes examined (median, 19 and 21, respectively). The number of patien ts with axillary metastasis was 39 (29.1%) in the ALND group and 68 (4 2.0%) in the SLND group (p < 0.03). Of these, 4 of 39 (10.3%) ALND pat ients (3.0% of all ALND patients) and 26 of 68 (38.2%) SLND patients ( 16.0% of all SLND patients) had micrometastasis (less than or equal to 2 mm), a highly significant difference (p < 0.0005). Conclusions Sent inel lymphadenectomy with multiple sectioning and immunohistochemical staining of sentinel nodes increases the accuracy of axillary staging in breast cancer and can identify significantly more patients with lym ph nodes metastases, especially micrometastases, than can ALND with ro utine histopathologic processing of lymph nodes.