Sentinel node biopsy after neoadjuvant chemotherapy in cytologically proven node-positive breast cancer

Several studies have assessed the feasibility of sentinel lymph node biopsy (SLNB) after NAC in patients with breast cancer, but diagnostic accuracy has varied. We prospectively evaluated the diagnostic accuracy of SLNB in detecting axillary lymph node (ALN) metastases after NAC in patients with cytologically proven positive nodes before chemotherapy.

We studied 95 breast cancer patients with cytologically proven positive nodes and a partial or complete clinical response to NAC in the breast lesions confirmed using magnetic resonance imaging. Patients then underwent SLNB followed by ALN dissection. The identification rate of sentinel lymph nodes (SLNs) and the false negative rate of nodal metastases were assessed. Subgroup analysis was conducted according to several clinical factors.

SLNs were successfully identified in 81 (85.3%) of the 95 patients. Among these 81 patients, 51 (63.0%) had ALN metastases on final pathologic examination after NAC. Eight of the 51 patients with ALN metastases had negative results on SLNB (false negative rate, 15.7%). Univariate analysis indicated that the false negative rate was significantly lower only in the HER2-negative group (P = .003).

SLNB after NAC did not correctly predict the presence or absence of axillary node metastases in patients with breast cancer who had cytologically proven positive nodes before NAC. However, the diagnostic accuracy might be different in cancer subtypes, therapeutic effect of chemotherapy, or sentinel lymph node status after chemotherapy. Well-powered studies are needed to confirm diagnostic accuracy of SLNB after NAC according to subgroup in patients with breast cancer.