Breast Sentinel Lymph Node Frozen Section Practice: An Enterprise Audit as a Guide for Moving Forward

Area of Science:

• Oncology
• Surgical Pathology
• Breast Cancer Management

Background:

• Decreased utilization of frozen section (FS) for sentinel lymph node (SLN) evaluation in breast cancer.
• Reduced emphasis on identifying small SLN metastases due to less aggressive surgical approaches.
• Need to assess current enterprise performance in SLN evaluation via FS.

Purpose of the Study:

• To critically evaluate institutional performance in evaluating axillary sentinel lymph nodes using frozen section (FS).
• To inform potential changes in processing protocols for SLN evaluation.

Main Methods:

• Retrospective review of SLN and nonsentinel lymph nodes from 426 patients (August 2017-July 2019).
• Evaluation of grossing technique and discordance between FS and permanent section (PS).
• Assessment of clinicopathologic features and adherence to serial sectioning at 2-mm intervals.

Main Results:

• Serial sectioning at 2-mm intervals was performed in 78.2% of cases, significantly lower in community sites (23.3%) vs. academic (87.1%).
• Overall discordance rate was 4.8% (21/432), all being false negatives.
• Of false negatives, 33.3% had macrometastatic disease; 15/16 sampling errors were detected on the first PS level.

Conclusions:

• Standard serial sectioning of SLNs at 2-mm intervals yields infrequent false negatives for macrometastatic disease.
• A single additional permanent section level is considered reasonable, provided serial sectioning protocols are followed.