Abstract 196P
Background
Axillary surgery in early breast cancer (BC) has become less radical. However, for patients (pts) undergoing NST, the optimal surgical treatment algorithm in the axilla remains uncertain and is influenced by response to NST. The significance of nodal micrometastases (ypN1mi) after NST remains controversial and detection of additional macrometastases could have impact on postneoadjuvant treatment decisions. The aim of our study was to retrospectively analyse ypN1mi occurrence in five neoadjuvant AGO B / GBG trials conducted between 2012 and 2019.
Methods
Data from 3199 pts with early BC, who were enrolled in five NACT studies (GeparSepto, GeparOcto, GeparNuevo, GeparX, GeparOla), were retrospectively analyzed. Our study investigated axillary surgeries, the incidence of ypN1mi and their correlation with outcome.
Results
3163/3199 (98.9%) patients underwent breast surgery and information available on axillary intervention and were included in our analysis. TNBC, HER2+ and HR+/HER2- BC were reported in 38.9%, 29.1% and 32.0% respectively. Nodal status upon clinical/imaging evaluation was cN0 in 66.5%, cN1 in 29.5% and cN2/cN3 in 3.9%. Sentinel lymph node biopsy (SLNB) prior to NST was performed in 44.1% (1395/3163) and after NST in 19.4%. 1746 pts did not have any axillary surgery prior to NST. After NST 612 pts had a SLNB only, 5 pts received a targeted lymph node biopsy (TLNB) only, 27 pts had a targeted axillary dissection (TAD) and 1288 pts received an axilla lymph node dissection (ALND) only. 125 pts had an ALND following SLNB, TLNB or TAD. Of the 2038 evaluable pts who had any LN surgery after NST 879 (43.1%) achieved a pathological complete response in the breast (ypT0) of which 47 (5.3%) had concurrent residual disease in the LNs (ypT0, ypN+). 2.7% had ypN1mi and 0.64% had ypN1mi as sole residual disease.
Conclusions
During our retrospective study period, surgical standards changed to preferring SLNB in cN0 and allowing TAD in cN+ patients both after NST starting 2017 and 2019 respectively. Surgical approaches according to cN stage, axillary conversion rates according to subtypes and 5 year TTE data will be presented.
Clinical trial identification
NCT01583426, NCT02125344, NCT02685059, NCT02682693, NCT02789332.
Legal entity responsible for the study
German Breast Group, GBG Forschungs GmbH.
Funding
The GeparSepto study was funded by BMS (Celgene) and Roche; the GeparOcto trial was financially supported by Amgen, Roche, TEVA and Vifor; the GeparNuevo trial was financially supported by AstraZeneca and the drug was supported by AstraZenca and BMS (Celgene); the GeparX trial was financially supported by Amgen and BMS (Celgene); the GeparOla study was financially supported by AstraZeneca.
Disclosure
T. Link: Other, Honoraria: Amgen, Roche, MSD, Novartis, Pfizer, Lilly, GSK, Gilead, AstraZeneca, Daiichi Sankyo; Non-Financial Interests, Other, Non-financial support: Pfizer, AstraZeneca, Gilead, Daiichi Sankyo and Stemline; Financial Interests, Advisory Board, Participates in advisory boards: MSD, Roche, Pfizer, Lilly, Myriad, Eisai, GSK, Gilead, Daiichi Sankyo and Roche. T.N. Fehm: Other, Honoraria: Onkowissen. J. Holtschmidt: Other, personal fees and non-financial support: Daiichi Sankyo; Other, non-financial support: Hologic; Other, personal fees: MSD Oncology, Novartis, Palleos Health Care, Pfizer, Roche Pharma, Seagen; Other, employee: GBG Forschungs GmbH; Financial Interests, Institutional, Funding, research funding: Abbvie, AstraZeneca, BMS, Daiichi Sankyo, Gilead, Novartis, Pfizer and Roche; Non-Financial Interests, Institutional, Other, medical writing: Daiichi Sankyo, Gilead, Novartis, Pfizer, Roche and Seagen; Other, GBG Forschungs GmbH has following royalties/patents: EP14153692.0, EP21152186.9, EP15702464.7, EP19808852.8 and VM Scope GmbH: Patents. S. Loibl: Other, Grants and other support: AbbVie, AstraZeneca, Celegene; Other support: Amgen, BMS, Lilly, Merck, Pierre Fabre, Relay Therapeutics, Sanofi; Other, Grants, non-financial support, and other support: Daiichi Sankyo, Immunomedics / Gilead, Novartis, Pfizer, Roche; Other, other support: Eirgenix, Eisai Europe Ltd., GSK; Other, Grants: Molecular Health; Other, non-financial support and other support: Seagen; Other, other support from Olema outside the submitted work: Olema; Other, Dr Loibl has a patent for EP14153692.0 pending, a patent for EP21152186.9 pending, a patent for EP15702464.7 issued, a patent for EP19808852.8 pending, and a patent for Digital Ki67 Evaluator issued and licensed: Patent. All other authors have declared no conflicts of interest.