Sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with operable breast cancer and positive axillary nodes at initial diagnosis.

Objective: To evaluate the utility of the sentinel lymph node biopsy (SLNB) in patients with operable breast cancer and positive axillary nodes at initial diagnosis treated with neoadjuvant chemotherapy (NAC).

Methods: A prospective study was performed from January 2008 to December 2012 in 52 women, mean age 50.7 years, with infiltrating breast carcinoma T1-3, N1, M0 (1 bilateral, 7 multifocal) treated with epirubicin/cyclophosphamide, docetaxel and trastuzumab in Her2/neu-positive patients. Axillary evaluation included physical examination, axillary ultrasound, and ultrasound-guided core needle biopsy of any suspicious lymph node. The day before surgery, 74-111 MBq of (99m)Tc-albumin nanocolloid was injected periareolarly. All patients underwent breast surgery, with SLNB and complete axillary lymph node dissection (ALND). The SLNs were examined by frozen sections, hematoxylin-eosin staining, immunohistochemical analysis or one-step nucleic acid amplification assay (OSNA).

Results: Mean tumor size: 3.5 cm. Histologic type: 81.1% invasive ductal carcinoma. Complete response of primary tumor was clinical 43.4%, pathological 41.5%. All patients were clinically node-negative after NAC. Pathological complete response of axillary node was 42.2%. SLN identification rate was 84.9%. Axilla was positive in the pathology study in 6 of 8 patients without nanocolloid migration. SLN accurately represented the axillary status in 95.5%. False negative rate was 8.3%. SLN was the only positive node in 68.2% of patients. Mean number of SLN removed was 1.9 and of nodes resected from the ALND 13.2.

Conclusions: SLN biopsy after NAC is a feasible and accurate tool in patients with operable breast cancer T1-3, N1 and clinically node-negative after therapy.