Evaluation of Intraoperative Frozen Section Analysis with Final Histopathology Results for Sentinel Lymph Node Biopsy: Z0011 Criteria Eligible Versus Ineligible Breast Cancer Patients.

Intraoperative frozen section analysis (FSA) of sentinel lymph nodes (SLNs) declined in the post American College of Surgeons Oncology Group Z0011 (ACOSOG Z0011) trial era. However, for those patients who do not meet the ACOSOG Z0011 criteria, FSA continues to be a valuable tool in intraoperative decision-making for axillary lymph node dissection (ALND). The aim of this study was therefore to retrospectively evaluate the benefit and accuracy of FSA of Z0011 criteria eligible versus ineligible patients and identify possible predictive factors for false negative results. Intraoperative FSA was performed on SLNs of 522 cT1-T3 breast cancer patients between 2008 and 2013. Clinicopathologic characteristics were retrospectively assessed by chart review. Overall FSA sensitivity and specificity was 67.8% and 100%. Sensitivity was generally higher for macrometastasis than for micrometastasis. The Z0011 eligible group showed a sensitivity and specificity of 72.7% and 100% versus 62.1% and 100% in the Z0011 ineligible group. Importantly, subgroup analysis of ≤ 2 versus > 2 positive SLNs of the Z0011 eligible group demonstrated both a 100% specificity and sensitivity. Several clinicopathologic factors were associated with a higher rate of false negative results in the Z0011 ineligible patient group. FSA was beneficial for 22.2% of Z0011 ineligible patients and for only 0.6% of Z0011 eligible patients regarding intraoperative decision-making for ALND. FSA continues to be especially beneficial in the intraoperative assessment of SLNs in the Z0011 ineligible group to prevent second stage ALND. Despite an overall lower FSA sensitivity in the Z0011 eligible patient group, FSA offers in both groups a comparable high sensitivity and diagnostic accuracy for macrometastasis.