Initial experience in a community hospital with sentinel lymph node mapping and biopsy for evaluation of axillary lymph node status in palpable invasive breast cancer

Background and Objectives: To determine the sentinel node detection rate an d the accuracy with which the sentinel node histology reflects that of the axilla in a series of patients with palpable invasive breast cancer. Methods: Forty-four patients with clinically node-negative palpable invasiv e T1 or T2 breast tumors underwent sentinel node biopsy using isosulfan blu e dye, followed immediately by either local excision of the primary lesion with standard axillary lymph node dissection or modified radical mastectomy . All surgeries were performed at Northwest Hospital, Seattle, Washington, between January 1996 and October 1997. Results: The sentinel node was successfully identified in 73% of the patien ts (32/44). The frequency of sentinel node detection was greater for tumors in the outer quadrants than the inner quadrants (z-test, P < 0.001). Of th e 32 patients in whom a sentinel node was identified, 10 (31%) had histolog ically positive sentinel nodes: 5 (16%) by frozen section, 2 additional pat ients (6%) after permanent hematoxalin-eosin (H&E) stained sections, and th e remaining 3 (9%) after immunohistochemical stains for cytokeratins when t he FS and permanent H&E-stained sections were beni,on. Twenty patients had benign axilla. The sentinel node was falsely negative in 2 patients, yieldi ng an accuracy of 93.8%, sensitivity of 83.3%, and negative predictive valu e of 91%. Conclusions: Lymphatic mapping is technically feasible for patients with sm all (T1 or T2) palpable invasive breast tumors. The sentinel node can be re liably identified in the majority of these patients, and its histology refl ects that of the axilla with a high degree of accuracy. Immunohistochemical stains and permanent H&E-stained sections of the sentinel node increased t he test's ability to correctly identify axillary metastases. Improving this sensitivity remains a primary goal, however, if benign sentinel node histo logy is to be used as a criterion to preclude axillary dissection. (C) 1999 Wiley-Liss, Inc.