Abstract PD8-02: Residual axillary involvement in early breast cancer in patients with positive sentinel nodes after neoadjuvant chemotherapy (NACT)
Authors: H-C Kolberg, C Liedtke, I Bauerfeind, T Fehm, B Fleige, M Hauschild, G Helms, A Lebeau, S Schmatloch, P Schrenk, L Schwentner, A Stäbler, S Loibl, M Untch, T Kühn
Journal: Cancer Research (2019)

Abstract Background:The association between pathological complete remission (pCR) in the breast and clinical/pathological parameters is well established, whereas the role of these parameters in the prediction of residual axillary involvement after NACT is unclear. The goal is to identify a subset of patients who do not need axillary treatment. We used data from Arm B of the SENTINA trial to analyze this association. Methods:Patients from arm B of the SENTINA trial with clinically and sonographically unsuspicious axillary nodes but with histologically proven involvement of SLNs prior to NACT were analyzed. All patients had SLNB and axillary dissection after NACT. Univariate analyses were performed to evaluate the association between clinical/pathological parameters and axillary involvement after NACT. Results:Arm B of the SENTINA study contained 360 patients, 318 of which were evaluable with respect to the above parameters. After NACT 71/318 (22.3%) patients had involved SLNs or non-SLNs; 71/318 (22.3%) had a pCR in the breast. We observed a significant association between pCR in the breast and negative ER status, negative PR status, positive HER2 status, triple negative (TN) status, tumor size before and after NACT, multifocality, lobular morphology and axillary involvement after NACT. Regarding residual axillary burden only the associations with lobular morphology, extracapsular invasion, multifocality, positive HER2 status and pCR in the breast were statistically significant. Conclusion:Our analysis demonstrates that patients enrolled in the SENTINA trial with clinically and sonographically unsuspicious axillary nodes but proven histological involvement of SLNs prior to NACT have positive axillary nodes in 22.3 % after NACT. This rate is confirming similar results from other groups. Although we found statistically significant associations between pCR in the breast and clinical/pathological parameters, only the association between lobular type, extracapsular invasion, positive HER2 status and pCR in the breast and residual axillary involvement after NACT were statistically significant. We cannot clearly identify a subset of patients for whom axillary treatment after NACT could be safely omitted if SLNs were positive. Our data are well in line with recently presented data demonstrating that the association between pCR in the breast and free axillary nodes after NACT is particularly strong in patients with TN and HER2 positive tumors. This question will be addressed in future trials currently under development. Citation Format: Kolberg H-C, Liedtke C, Bauerfeind I, Fehm T, Fleige B, Hauschild M, Helms G, Lebeau A, Schmatloch S, Schrenk P, Schwentner L, Stäbler A, Loibl S, Untch M, Kühn T. Residual axillary involvement in early breast cancer in patients with positive sentinel nodes after neoadjuvant chemotherapy (NACT) [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 PD8-02.