Abstract P3-03-43: Incorporation of MSKCC nomogram to guide the application of intra-operative sentinel lymph node frozen section evaluation in patients with early breast cancer

Abstract

Abstract Background and Objectives: Although de-escalation of axillary surgery becomes more popular, axillary lymph node dissection (ALND) is still the standard care for sentinel lymph node(SLN) positive patients not meeting the criteria of ACOSOG Z0011 in many hospitals, and frozen section (FS) of SLN is one of the valuble intra-operative assesments to avoid axilla re-operation although it was controversial due to accuracy and efficiency concerns. This study was to assess the performance of selective use of frozen section evaluation guided by MSKCC lymph node metastasis risk prediction nomogram to optimize the proceudure to be more accurate and cost effective. Methods: Surgical pathology records of consecutive 2582 biopsies in 2552 patients breast cancer patients from 2011 to 2017 were reviewed, intra-operative frozen section diagnosis were compared to post-operative paraffin reports. We calculated the sensitivity, specificity, accuracy and FNR for different MSKCC risk, the axilla re-operation rate with or without FS and the number needed to treat (NNT) to avoid second ALND was also analyzed. Results: The sensitivity, specificity, and FNR of FS were 84.7%, 99.9%, and 15.3% respectively. The axilla re-operation rates were significantly decreased if FS was done(4.7%±0.4% with FS versus 35.8%±5.8% without FS, P<0.001). The estimated axilla re-operation rate without FS was positively correlated with MSKCC risk(r=0.99, P<0.001), while NNT to avoid second ALND by FS were negatively correlated with MSKCC risk(r=-0.98, P<0.001). When patients were divided into four groups according to quartile MSKCC risk, the axilla re-excisional rates were 18.4%, 25.1%, 38.7%, 58.7% without FS, while 4.8%, 3.2%, 5.6%, 3.2% with FS, and NNT correspondingly decreased from 7.3, 4.5, 3.0 to 1.8. An decision-making algorithm for application of FS was proposed. Conclusion: Stratified decision-making algorithm based on MSKCC prediction model improved the efficiency of FS to avoid axilla re-operatioin in patients undergoing sentinel lymph node biopsy. We recommend FS be restricted to patients with MSKCC risk higher than 0.5 who do not meet ACOSOG Z0011 criteria. Citation Format: Yang H, Wang S, Shen D, Cao Y, Tong F, Chen D, Liu P, Peng Y. Incorporation of MSKCC nomogram to guide the application of intra-operative sentinel lymph node frozen section evaluation in patients with early breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-43.