Sentinel lymph node biopsy as a way of assessing breast cancer after chemotherapy

This study investigated sentinel lymph node biopsy (SLNB) as a procedure to determine the staging of breast cancer in patients who had received neoadjuvant chemotherapy (chemotherapy given before surgery). The authors concluded that SLNB was suitable for staging of the cancer in patients with breast cancer that had not spread to the lymph nodes and who had received chemotherapy prior to surgery. 

Examination of the underarm lymph nodes is very important to assess if breast cancer has spread to the lymphatic system (a network of vessels that is part of the immune system and carries fluid called lymph around the body). It is also important for deciding upon the best treatment option. Axillary lymph node dissection (ALND) has traditionally been used to predict the stage of breast cancer in patients. This is where all the underarm lymph nodes are removed. ALND can cause complications such as swelling, numbness, pain, and restriction of movement in the shoulder. These can affect the patient’s quality of life. It is known that SLNB results in fewer complications, and is a recommended alternative to ALND. In SLND only the first few lymph nodes that the tumor drains into are removed. If these nodes are cancer free, then it is unlikely the cancer has spread and removing more lymph nodes is unnecessary.

Neoadjuvant chemotherapy (NAC) is treatment given before surgery to treat patients with locally advanced breast cancer. Whether using SLNB after NAC is a useful method to stage breast cancer is unclear. 

This study examined the accuracy of SLNB following neoadjuvant chemotherapy. The research included the results from 16 prior studies. A total of 1,456 patients who had breast cancer (but no cancer in the lymph nodes) at the time of diagnosis were assessed. All patients underwent SLNB after NAC. All patients then underwant axillary lymph node dissection.

The use of SLNB was able to identify axillary lymph node involvement in 96% of cases. The false negative rate was 6%.

The study concluded that SLNB is an accurate method for predicting axillary lymph node involvement in patients who were initially diagnosed with no cancer in the lymph nodes.