Abstract P3-01-11: Sentinel lymph node (SLN) localization is highly successful after neoadjuvant chemotherapy (NCT) for breast cancer

Abstract

Background: Recent multi-center trial results are concerning for the ability to identify SLNs after NCT. SLN localization was shown to be less successful (80%) after NCT when compared with no NCT (99%) (SENTINA), and the SLN identification rate in Z1071 in which all patients received NCT was 93%. Purpose: To examine the effect of NCT, patient and disease characteristics, imaging and surgical technique on SLN localization rates in breast cancer patients undergoing chemotherapy. Methods: Retrospective, single institution study was performed on patients who underwent surgery for breast cancer from January 2008 to December 2013. All patients who underwent SLN biopsy and either adjuvant chemotherapy (ACT) or NCT, were included. All patients underwent lymphoscintigraphy, and SLN biopsy was performed with the definitive breast surgery. Results: 68 patients underwent NCT, and 133 underwent ACT. Our SLN localization rate was 198/201 (98.5%) overall; 98.6% (67 of 68) with NCT and 97.7% (130/133) with ACT (p=1.0). Compared with the NCT group, the ACT patients were significantly older, white, with more ER/PR positive tumors. The NCT group had more positive nodes on preop imaging (64% v. 20%, p<0.001), FNA (82% v. 22%, p<0.001), and a lower use of blue dye (37% v. 61%, p=0.05) but there were no differences in the number of SLN removed (1.43 v. 1.33 p=0.32), or nodes that were positive on intraoperative evaluation (30 v. 33%, p=0.75). Comparing the patients who had successful and failed SLN localization, there were no differences in demographics, tumor type, Stage, prior breast surgery, preoperative node positivity on imaging or FNA or timing of chemotherapy. Conclusion: In this single institution series, SLN non-localization was a rare event and not associated with NCT. We were unable to identify any patient or disease characteristics, imaging or surgical techniques associated with SLN non-localization. The etiology of the lower SLN identification rates with NCT in multi-institutional trials remains to be elucidated. Citation Format: Sugg S, Hayes R, Gbenon A, Lizarraga I, Erdahl L, Weigel R, Liao J, Menda Y, Scott-Conner C. Sentinel lymph node (SLN) localization is highly successful after neoadjuvant chemotherapy (NCT) for breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-01-11.