Comprehensive examination of sentinel lymph node in breast cancer: a solution without a problem?

Area of Science:

• Oncology
• Surgical Pathology
• Breast Cancer Diagnostics

Background:

• Sentinel lymph node (SLN) biopsy is crucial for breast cancer staging.
• The optimal examination extent for SLN specimens, particularly for micrometastases (MM), remains debated.
• Multilevel sectioning is proposed to enhance MM detection but its routine utility is questioned.

Purpose of the Study:

• To evaluate the diagnostic yield of multilevel sectioning in SLN biopsies for breast cancer.
• To determine if extended sectioning protocols improve the detection of micrometastases (<2.0 mm).

Main Methods:

• Retrospective review of 67 positive SLN biopsies from breast cancer patients.
• Specimens were evaluated using an extended protocol including multilevel sectioning.
• Comparison of findings across different sectioning intervals (100–500 micrometers).

Main Results:

• Metastatic deposits varied: micrometastases (0.2–1.0 mm, 1.0–2.0 mm), larger metastases (>2.0 mm), and isolated tumor cells (ITCs).
• Sectioning intervals did not significantly alter the likelihood of finding metastatic deposits >2.0 mm.
• One 1.1 mm micrometastasis was missed at 250- and 500-microm intervals without cytokeratin staining.

Conclusions:

• Multilevel sectioning of SLN biopsies offers no significant additional yield over standard examination for detecting micrometastases of at least 1.0 mm.
• Routine multilevel sectioning may not be necessary if the primary goal is to identify micrometastases of 1.0 mm or larger.