Sentinel lymph node biopsy is accurate after neoadjuvant chemotherapy for breast cancer

Purpose: Sentinel lymph node (SLN) biopsy has proved to be an accurate meth od for detecting nodal micrometastases in previously untreated patients wit h early-stage breast cancer. We investigated the accuracy of this technique for patients with more advanced breast cancer after neoadjuvant chemothera py. Patients and Methods: Patients with stage II or III breast cancer who had u ndergone daxorubicin-based neoadjuvant chemotherapy before breast surgery w ere eligible. Intraoperative lymphatic mapping was performed with peritumor al injections of blue dye alone or in combination with technetium-labeled s ulfur colloid. All patients were offered axillary lymph node dissection. Ne gative sentinel and axillary nodes were subjected to additional processing with serial step sectioning and immunohistochemical staining with an anticy tokeratin antibody to detect micrometastases. Results: Fifty-one patients underwent SLN biopsy after neoadjuvant chemothe rapy from 1994 to 1999. The SLN identification rate improved from 64.7% to 94.1%. Twenty-two (51.2%) of the 43 successfully mapped patients had positi ve SLNs, and in 10 of those 22 patients (45.5%), the SLN was the only posit ive node. Three patients had false-negative SLN biopsy; that is, the sentin el node was negative, but at least one nonsentinel node contained metastase s. Additional processing revealed occult micrometastases in four patients ( three in sentinel nodes and one in a nonsentinel node). Conclusion: SLN biopsy is accurate after neoadjuvant chemotherapy, The SLN identification improved with experience. False-negative findings occurred a t a low rate throughout the series. This technique is a potential way to gu ide the axillary treatment of patients who are clinically node negative aft er neoadjuvant chemotherapy. (C) 2000 by American Society of Clinical Oncol ogy.