Abstract OT1-04-04: AXSANA - EUBREAST 3 (axillary surgery after neoadjuvant treatment): An international prospective multicenter cohort study of the EUBREAST study group to evaluate different surgical methods of axillary staging (sentinel lymph node biopsy, targeted axillary dissection, axillary dissection) in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy (NCT04373655)

Abstract Background The optimal surgical staging procedure of the axilla in patients who convert from a clinically positive (cN+) to a clinically negative node status (ycN0) through neoadjuvant chemotherapy is still controversial. Widely diverse techniques such as full Axillary Lymph Node Dissection (ALND), Targeted Axillary Dissection (TAD), Targeted Lymph Node Biopsy (TLNB) and Sentinel Lymph Node Biopsy alone (SLNB) are given preference in different international guidelines. So far, no comparative data on the oncological outcome or the morbidity of the different procedures are available. Further research is needed to safely de-escalate the extent of axillary surgery in this patient group. Trial design The AXSANA study is an international prospective cohort study including cN+ patients converting to ycN0 status and treated with different axillary staging techniques according to the standard at their treating institution. The study is initiated by the EUBREAST network. The trial includes patients with cT1-4c tumors, who present initially with axillary lymph node metastasis and are scheduled for neoadjuvant chemotherapy. According to an amendment in 2020 the inclusion of patients with highly suspicious nodes without minimally invasive biopsy is allowed. All patients converting to ycN0 status undergo follow-up for 5 years irrespectively of the ypN status. Primary endpoints: Invasive disease-free survival, axillary recurrence rate and health-related quality of life (HRQoL). HRQoL are evaluated using four standardized questionnaires (EORTC QLQ-C 30, EORTC QLQ BR 23, Lymph ICF and SOC-13) at baseline and after 1, 3 and 5 years after surgery. Secondary endpoints are the feasibility and performance of different axillary staging techniques (detection rate, number of removed lymph nodes and association with complications, arm morbidity and quality of life, operating time and use of clinical and economic resources); impact of learning curve, and the detailed mapping of surgical and oncological treatment standards in different countries. The impact on different regional treatment strategies (radiotherapy, ALND) in patients with ypN0(i+), ypN1(mi) and ypN1 is assessed. Current status of the study: On June 30th 157 study sites from 15 countries are open for recruitment (Austria 2, Czech Republic 1, Finland 1, Germany 112, Greece 3, Italy 1, Norway 1, Poland 3, Portugal 5, Romania 2, Russia 1, Sweden 4, Switzerland 4, Spain 6, Turkey 11). 620 patients have been included in the study. Among patients who converted to ycN0 status, 144 have been scheduled for ALND, 157 for TAD and 49 for SLNB. The study is still open for further international study sites. Funding: AGO-B, Claudia-von Schilling Foundation, Ehmann Foundation, AWOgyn, Merit Medical, Endomagnetics, Mammotome Target accrual: 3000 patients worldwide Citation Format: Thorsten Kühn, Steffi Hartmann, Elmar Stickeler, Jana de Boniface, Oreste Gentilini, Sarah Fröhlich, Franziska Ruf, Marc Thill, Michael Hauptmann, Guldeniz Karadeniz Cakmak, Isabel Rubio, Maria Luisa Gasparri, Michaelis Kontos, Eduard-Alexandru Bonci, Laura Niinikoski, Rosa Di Micco, Dawid Murawa, David Pinto, Florentia Peintinger, Christine Solbach, Matilda Appelgren, Jens-Uwe Blohmer, Michael Weigel, Gabriele Kaltenecker, Michael Schrauder, Janine Simons, Marjolein Smidt, Ellen Schlichting, Lukas Dostalek, Alexander Sergeevich Emelyanov, Elisabeth Thiemann, Semra Gunay, Sybille Loibl, Maggie Banys-Paluchowski. AXSANA - EUBREAST 3 (axillary surgery after neoadjuvant treatment): An international prospective multicenter cohort study of the EUBREAST study group to evaluate different surgical methods of axillary staging (sentinel lymph node biopsy, targeted axillary dissection, axillary dissection) in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy (NCT04373655) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT1-04-04.