Can a seed-sized tool from Texas spare clinically node positive breast cancer patients from a complete axillary dissection?

Axillary lymph node status guides both treatment course and prognosis in patients with breast cancer. When patients receiving neoadjuvant chemotherapy (NAC) are excluded, NCCN guidelines call for a sentinel node (SN) biopsy in clinically node negative stage I and II patients, followed by complete axillary lymph node dissection (ALND) only if there is a SN metastasis and the patient does not meet eligibility criteria for the ACOSOG Z0011 trial (1). In the remainder, ALND can be omitted. Testing whether this concept can be extended to patients diagnosed pre-operatively as both node positive and scheduled to receive NAC has been the subject of multiple investigations; their impetus being the desire to reduce ALND and its attendant morbidity (2-6). Avoiding ALND in patients identified as node positive pre-operatively by needle biopsy requires evidence that a negative SN biopsy after NAC is an adequate proxy for the status of the axilla; i.e., the false negative rate (FNR) is low. The FNR for SN biopsy in patients undergoing surgery as their first cancer treatment has consistently been shown to be less than 5–10%. Whether this low FNR can be replicated in the post-NAC setting was recently reported by investigators from the MD Anderson Cancer Center in the Journal of Clinical Oncology (April 2016) (7). Building on prior trials that measured both the SN identification rate and the FNR after NAC (2-6), a novel approach termed targeted axillary dissection (TAD) was developed to compare its efficacy to accurately stage the axilla compared to SN biopsy alone. TAD presupposes that the patient’s SN status after NAC potentially differs from the status of the node found to be positive pre-NAC; thus if both are removed, the FNR may be improved. With TAD, the node found to be positive preoperatively is marked with a clip during the time of needle biopsy, then later removed after NAC using a radioactive seed localization technique. TAD combines a standard two dye SN biopsy technique with removal of the clipped node found to be positive on pre-NAC needle biopsy