Update on sentinel node pathology in breast cancer.

Area of Science:

• Oncology
• Surgical Pathology
• Breast Cancer Research

Background:

• Recent trials have altered sentinel lymph node biopsy (SLNB) practices in breast cancer.
• The ACOSOG Z0011 trial reduced axillary lymph node dissection (ALND) for early-stage disease with limited positive SLNs.
• Evidence for neoadjuvant therapy patients is evolving, as they were excluded from key trials.

Purpose of the Study:

• To review evidence-based best practices for sentinel lymph node evaluation in breast cancer.
• To discuss the role of intraoperative SLN evaluation and immunohistochemistry (IHC) in specific patient populations.
• To inform clinical decision-making regarding SLN assessment post-neoadjuvant therapy.

Main Methods:

• Literature review of landmark trials and recent studies on SLNB and ALND in breast cancer.
• Analysis of the impact of neoadjuvant therapy on SLN evaluation criteria.
• Discussion of the utility of cytokeratin immunohistochemistry (IHC) for detecting micrometastases.

Main Results:

• ALND rates have decreased for early-stage breast cancer following ACOSOG Z0011.
• SLNB is safe and accurate for clinically node-negative patients receiving neoadjuvant therapy.
• Cytokeratin IHC may improve detection of small metastases in post-neoadjuvant cases.

Conclusions:

• Intraoperative SLN evaluation retains value for surgical decision-making.
• ALND is standard for residual disease in SLNs.
• Further data from ongoing trials are needed for definitive recommendations in neoadjuvant cases.