Clipped Node Pathology as a Guide for Limited Axillary Surgery in Occult Breast Cancer.

Area of Science:

• Oncology
• Surgical Oncology
• Breast Cancer Research

Background:

• Occult breast cancer (OBC) diagnosis presents unique challenges for treatment and staging.
• Current guidelines mandate axillary lymph node (ALN) dissection for OBC, yet these patients are underrepresented in studies on de-escalating axillary surgery.
• Limited data exists on the effectiveness of neoadjuvant systemic therapy (NST) and subsequent axillary staging strategies in OBC.

Purpose of the Study:

• To evaluate the rate of pathologic complete response (pCR) in OBC patients treated with NST.
• To determine if the pathology of the pre-treatment biopsy-proven clipped ALN can predict the residual axillary disease burden after NST.
• To assess the potential for de-escalating axillary surgery in selected OBC patients.

Main Methods:

• An observational cohort study analyzed data from OBC patients diagnosed between 2010 and 2025.
• The study estimated pCR rates across different breast cancer subtypes (HR+/HER2-, HER2+, HR-/HER2-).
• Diagnostic test characteristics (specificity, false-negative rate) of the clipped node pathology were calculated to evaluate residual axillary disease.

Main Results:

• pCR rates varied by subtype: 33.3% for HR+/HER2-, 83.3% for HER2+, and 77.4% for HR-/HER2- disease.
• A clip was placed in the biopsy-proven positive node in 54.1% of patients.
• Pathologic assessment of the clipped node demonstrated 88.6% specificity and a 13.3% false-negative rate in all OBC patients, with 0% FNR in cN1/cN2 disease.

Conclusions:

• Pathologic evaluation of the clipped axillary lymph node is a reliable indicator of residual disease burden in OBC patients post-NST.
• Limited axillary surgery, focusing on the clipped node, is a viable staging strategy for selected OBC patients, particularly those with cN1 or cN2 disease.
• This approach may allow for de-escalation of axillary surgery in occult breast cancer management.