What is the role of targeted axillary dissection (TAD) in breast cancer management?

From the Guidelines

Targeted axillary dissection (TAD) is the recommended approach for evaluating axillary lymph node status in breast cancer patients with initially positive nodes who receive neoadjuvant chemotherapy. This technique combines sentinel lymph node biopsy with the removal of specific lymph nodes that were initially positive and marked with a clip or seed before chemotherapy, providing more accurate staging information while reducing the need for complete axillary lymph node dissection, which carries higher risks of lymphedema, nerve damage, and shoulder dysfunction 1. The procedure typically involves injecting radioisotope and/or blue dye around the tumor or areola to identify sentinel nodes, along with ultrasound guidance or a radioactive seed localization to remove the previously clipped node.

Key Benefits of TAD

• Reduces false-negative rates to approximately 2-4%, compared to 10-15% with sentinel node biopsy alone 1
• Allows surgeons to de-escalate axillary surgery in patients who have had a good response to chemotherapy, preserving arm function while still providing accurate staging information to guide further treatment decisions like radiation therapy
• Patients undergoing TAD should expect a shorter recovery time and fewer complications than traditional axillary dissection

Important Considerations

• The use of a dual tracer has been shown to lower false-negative rates, and removing more than 2 sentinel nodes can further improve accuracy 1
• The clipped node should be removed, and more than 2 sentinel nodes should be removed to minimize false-negative rates 1
• TAD is a suitable option for patients with clinically node-negative or small-volume nodal disease who undergo neoadjuvant chemotherapy, and it can be used to determine the need for radiation therapy 1

Clinical Evidence

• The ACOSOG Z1071 multicenter trial evaluating the effectiveness of SLNB after NAC reported a detection rate of 93% and the FNR of 13% 1
• The SENTinel NeoAdjuvant study consisting of initially clinically node-positive patients who converted to ycN0 after NAC reported overall FNR of 14.2%, which decreased to 8.6% if a dual tracer was used, and further decreased to 7% if 3 SLNs were removed 1

From the Research

Targeted Axillary Dissection in Breast Cancer

• Targeted axillary dissection (TAD) is a technique that combines sentinel lymph node biopsy with the removal of the previously marked metastatic node, aiming to improve axillary staging and reduce false negative rates after neoadjuvant chemotherapy in breast cancer patients 2, 3, 4.
• The feasibility of TAD has been assessed in several studies, with results showing that it is a reliable approach for axillary staging after neoadjuvant chemotherapy, with high detection rates and low false negative rates 2, 4, 5.
• TAD has been compared to sentinel lymph node biopsy (SLNB) alone, with studies showing that TAD has a lower false negative rate than SLNB alone 2, 5.
• The use of TAD can spare some patients from axillary lymph node dissection (ALND), reducing the risk of lymphedema and other complications 3, 4, 5.
• The preoperative localization of the clipped node is crucial to increase the detection rate and optimize the results of TAD 2, 4.
• The oncological safety of TAD still needs to be verified, with long-term follow-up studies required to assess its efficacy and safety 3, 5.

Key Findings

• A study of 455 patients with invasive breast cancer found that TAD had a detection rate of 100% and a false negative rate of 5.0% 2.
• A retrospective study of 121 breast cancer patients found that TAD was associated with a false negative rate of 0% and that 23 patients were spared from ALND 3.
• A prospective study of 37 breast cancer patients found that TAD had a detection rate of 97.3% and that 19 patients were spared from ALND 4.
• A systematic review and pooled analysis of 9 studies found that TAD was associated with a false negative rate of 5.18% and that it was a valid alternative to complete axillary lymph node dissection in patients with node-positive breast cancer after neoadjuvant chemotherapy 5.

Axillary Node Interventions

• A systematic review of 17 studies found that complete axillary node dissection was associated with a 14% risk of lymphedema and that sentinel node biopsy alone was sufficient for patients with no suspicious, palpable axillary nodes who undergo breast-conserving therapy 6.
• The review also found that surgical axillary staging via sentinel node biopsy helps to inform decisions regarding adjuvant systemic and radiation therapy, and that complete axillary node dissection is indicated in patients who present with palpable or needle biopsy-proven axillary metastases 6.