Advantage of sentinel lymph node biopsy before neoadjuvant chemotherapy in breast cancer treatment.

Lymph node status is a key factor in determining the stage of breast cancer and the most appropriate therapy and for predicting the outcome of patients. Accurate identification of sentinel lymph nodes (SLNs) preoperatively is of clinical importance. Sentinel lymph node biopsy (SLNB) causes less lymph edema of the upper arm than axillary lymph node dissection (ALND) with a high accuracy rate and low false-negative rate (FNR). Neoadjuvant chemotherapy (NAC) can be given not only to patients with locally advanced breast cancer, but also to those with axillary lymph node metastasis and an operable tumor. However, SLNB after NAC results in a lower identification rate and a higher FNR than SLNB before treatment. Recently, a hybrid imaging device has been developed, which consists of single photon emission computed tomography (CT, SPECT) and a low-dose CT installed on the same platform. This imaging system offers an easy and safe method of performing SLNB under local anesthesia. To identify the initial cancer stage in patients who will be treated by systemic therapy before surgery, SLNB should be performed prior to systemic treatments, using a well-developed navigating tool, such as SPECT/CT.