Sentinel Lymph Node Removal After Neoadjuvant Chemotherapy in Clinically Node-Negative Patients: When to Stop?

Area of Science:

• Oncology
• Surgical Oncology
• Breast Cancer Research

Background:

• Accurate axillary staging is crucial for breast cancer patients undergoing neoadjuvant chemotherapy (NAC).
• The optimal number of sentinel lymph nodes (SLNs) to resect after NAC for clinically node-negative (cN0) disease remains undetermined.
• Understanding the sequence of positive SLN identification is key to refining surgical protocols.

Purpose of the Study:

• To determine the maximum number of SLNs needed for accurate axillary staging in cN0 breast cancer patients receiving NAC.
• To investigate the sequence of positive SLN identification during surgery.

Main Methods:

• Retrospective analysis of 440 cN0 invasive breast cancer patients who received NAC and SLN surgery (2008-2018).
• Univariate analysis to identify factors associated with positive nodes and the location of the first positive SLN.
• Evaluation of the number of SLNs removed and their pathological status (ypN0 vs. ypN+).

Main Results:

• Of 446 cancers, 14.6% were pathologically node-positive (pN+) post-NAC.
• The median number of SLNs removed was 2.0 for both ypN0 and ypN+ patients.
• The first positive SLN was most commonly the 1st node removed (75.4%) and was identified within the first three SLNs in all cases.

Conclusions:

• In cN0 breast cancer patients treated with NAC, the first positive SLN is usually identified within the first three nodes removed.
• Resecting more than three SLNs after NAC may not provide additional diagnostic value for axillary staging.
• This finding supports optimizing SLN surgery protocols to potentially reduce unnecessary resections.