Targeted Axillary Dissection (TAD): Not to be Confused with Axillary Lymph Node Dissection

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Heather Donohue

Educator & Internship Program Manager

The terminology in breast cancer lymph node surgeries can be confusing and lead to miscoding of the Scope of Regional Lymph Node Surgery field, which in turn could negatively impact research on treatment efficacy and patient outcomes. It is imperative that cancer registrars understand the different surgical terminology and definitions, and practice diligence when reading operative reports.

Breast cancer patients with clinically suspicious lymph nodes, during the clinical timeframe, will have a biopsy to confirm or disprove involvement. Previously, for patients with  histologically confirmed positive axillary lymph nodes, the NCCN Guidelines surgical recommendations were to perform an Axillary Lymph Node Dissection of level I/II lymph nodes; Level III lymph nodes would only be removed when evidence of gross level II/III disease was discovered. Post surgical morbidities following Axillary Lymph Node Dissection include life-long lymphedema, due to removal of the lymph nodes and channels to move/remove fluids, and possible numbness, tingling, and paresthesia in the affected axillary region and arm. Axillary Lymph Node Dissection may lead to a decrease in quality of life for breast cancer survivors, which has been recognized by the medical profession for some time.   

A group of surgeons out of MD Anderson hypothesized that a select group of patients could possibly be spared of invasive axillary surgery, and life-altering post surgical morbidities. This group pioneered the Targeted Axillary Dissection (TAD). They began their studies in 2015 with early and promising results shared in January 2016. The study showed that most patients who were clinically node positive by biopsy, who received neoadjuvant therapy, and had an excellent response did not need a more invasive Axillary Lymph Node Dissection, as previous NCCN Guidelines recommended. 

Targeted Axillary Dissection is now included in the NCCN Guidelines for patients who are cT1-T3 N1(f) M0. When axillary lymph nodes are histologically confirmed positive, patients will have a tattoo or clip marker placed to later identify the positive node. In patients who receive neoadjuvant therapy, pre-surgical imaging will be performed to assess the response to therapy. In patients who become  ycN0, a radioactive iodine-125 seed or magnetic seed (Magseed) will be inserted in the previously tattooed or clipped metastatic node to easily identify and remove the lymph node at time of surgery. A dual tracer Sentinel Lymph Node Biopsy  will be performed. At least 3 SLNs should be removed with the gamma probe, following blue dye injection, and the i-125 or Magseed probe that will detect and locate the previously positive LN(s); other identified nodes in the area may also be “selectively” removed. If nodes are negative on the frozen section, an Axillary Lymph Node Dissection does not need to be carried out. Scope of Regional Lymph Node Surgery is coded as 2, Sentinel Lymph Node Biopsy. All nodes removed are coded as Sentinel Lymph Nodes in the SLN Positive/Examined fields. 

From the Breast v3.2024 NCCN Guidelines:

 “Among patients shown to be N+ prior to preoperative systemic therapy, SLNB has a >10% false-negative rate when performed after preoperative systemic therapy, which can be improved by marking and removing the most suspicious biopsied node, using dual tracers, and by obtaining ≥3 sentinel nodes (targeted axillary lymph node dissection). (Caudle AS, et al. J Clin Oncol 2016;34:1072-1078.)”. 

Identifying a true Axillary Lymph Node Dissection 

Additional Sources: 

Md Anderson: Breast Cancer – Invasive Stage I-III

2018 NCCN Guidelines 

2020 NCCN Guidelines