Background: After neoadjuvant chemotherapy, while results of sentinel node biopsy (SNB) are encouraging, conditions that may affect sentinel node (SN) detection and false negative rates with respect to clinical and pathological tumor response after neoadjuvant therapy require investigation.

Methods: Thirty-four patients with clinical stage I, II and IIIA invasive breast cancer underwent neoadjuvant chemotherapy with doxorubicin/cyclophosphamide or doxorubicin/cyclophosphamide and docetaxel/segmental resection, SNB, and axillary node dissection (AND).

Results: SNs were found in 31 of 34 patients (91.2%). SNs were found in 20 of 21 patients (95.2%) with complete clinical tumor response, it was positive in 40% and no false negatives occurred. SNs were found in 11 of 13 patients (84.6%) with partial or no clinical tumor response; in four patients (33%) the SN was positive and no false negative nodes were found. Seven patients had complete pathological tumor response. SNs were found in six of these patients (85.7%). The SN was positive in 1 of 6 patients (16.7%) with no false negative. In 25 of 27 patients (92%) with partial or no pathological tumor response, the SN was identified. Eleven of these patients (44%) had positive nodes with no false negatives.

Conclusions: SN identification rate and accuracy after neoadjuvant chemotherapy for breast carcinoma were extremely good however there is potential for inaccuracy after less than complete pathological tumor response. Further evaluation of SNB in larger clinical trial is warranted prior to accepting this approach as a standard care.