Increased false negative sentinel node biopsy rates after preoperative chemotherapy for invasive breast carcinoma

BACKGROUND. Sentinel lymph node dissection (SLND) has been a promising new technique in breast carcinoma staging, but could be unreliable in certain p atient subsets. The current study assessed whether age, preoperative chemot herapy, tumor size, and/or previous excisional biopsy influenced the identi fication of sentinel nodes (SLNs) or the reliability of a node-negative SLN D in predicting a node negative axilla. METHODS, Eighty-two patients who had clinically negative axillae underwent SLND followed by Level I/II axillary lymph node dissection (ALND). SLNDs we re performed using both technetium-99m (Tc-99m) labeled colloid and isosulf an blue dye. SLNs were analyzed by hematoxlyin and eosin and immunocytochem ical techniques. RESULTS, SLNs were successfully identified in 80% of patients. Mapping succ ess was decreased among postmenopausal women but was not influenced by preo perative chemotherapy, large tumor size, or previous excisional biopsy. Of the 31 successfully mapped, node positive patients, 5 had false negative (F N) SLNDs (overall FN rate = 16%). Of the 9 successfully mapped patients who had received preoperative chemotherapy and had positive axillary nodes, 3 had FN SLND (FN rate = 33%). The presence of clinically positive lymph node s before chemotherapy did not predict which patients would have a subsequen t FN SLND. T3 tumor size, but not previous excision, was associated signifi cantly with increased FN rate, although the FN rate for previous excision w as 11%. No FN SLND occurred with T1/T2 tumors that were not excised previou sly and had not received preoperative chemotherapy. CONCLUSIONS, Preoperative chemotherapy was associated with an unacceptably high FN rate for SLND. While larger tumor size also was associated with FN SLND, this effect might have been due to preoperative chemotherapy use in t hese patients. Small sample size precluded determining whether excisional b iopsy before mapping increased FN SLND rates independently. Cancer 2000;89: 2187-94. (C) 2000 American Cancer Society.