Abstract P2-10-25: AXSANA: Status of the international prospective multicenter cohort study evaluating different surgical methods of axillary staging in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy (NCT0437365

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) after neoadjuvant chemotherapy (NACT) is still controversial. Diverse techniques such as Axillary Lymph Node Dissection (ALND), Targeted Axillary Dissection (TAD), Target Lymph Node Biopsy (TLNB), and Sentinel Lymph Node Biopsy (SLNB) alone are given preference in different international guidelines. So far, no prospective comparative data on the oncological outcome or the morbidity by procedure are available. Further research is needed to de-escalate axillary surgery in this patient group safely. Trial design AXSANA is an international prospective cohort study including initially cN+-patients converting to ycN0-status after NACT and treated with different axillary staging techniques according to the standard at their treating institution. AXSANA was initiated by the EUBREAST (European Breast Cancer Research Association of Surgical Trialists) network and includes patients with cT1-4c tumors, who present initially with axillary lymph node metastasis scheduled for neoadjuvant chemotherapy. According to an amendment in 2020, the inclusion of patients with highly suspicious nodes without confirmation using a minimally invasive biopsy is allowed. All patients converting to ycN0 status undergo follow-up for 5 years regardless of the ypN status. Primary endpoints: Invasive disease-free survival, axillary recurrence rate, and health-related quality of life (HRQoL). HRQoL is evaluated using four standardized questionnaires (EORTC QLQ-C 30, EORTC QLQ BR 23, Lymph ICF, and SOC-13) at baseline and 1, 3, and 5 years after surgery. Secondary endpoints: Feasibility and performance of different axillary staging techniques (detection rate, number of removed lymph nodes and association with complications, 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 effect on different regional treatment strategies (radiotherapy, ALND) in patients with ypN0(i+), ypN1(mi), and ypN1 is assessed. Current status of the study: 5,499 patients from 290 study sites and 27 countries were enrolled in the study between June 2020 and June 2024. Among 3,382 ycN0-patients with a defined surgical concept 909 (26.8%) women were scheduled for ALND, 1,817 (53.6%) for TAD, 547 (16.2%) for SLNB, 19 for TLNB (0.7%) and 90 (2.7%) for other procedures. A target lymph node was marked in 3,099 patients, most frequently using clips/coils (2,418, 78.0%), followed by magnetic seeds (n=320, 10.3%), carbon ink (n=228, 7.4%), and radar markers (n=138, 4.5%). Funding: AGO-B, Claudia-von Schilling Foundation, Ehmann Foundation, Eugen und Irmgard Hahn Foundation, AWOgyn, Merit Medical, Endomagnetics, Mammotome Target accrual: unlimited Citation Format: Maggie Banys-Paluchowski, Nina Ditsch, Elmar Stickeler, Jana de Boniface, Oreste D. Gentilini, Michael Hauptmann, Guldeniz Karadeniz Cakmak, Isabel T. Rubio, Maria L. Gasparri, Michalis Kontos, Eduard-Alexandru Bonci, Laura Niinikoski, Dawid Murawa, Geeta Kadayaprath, David Pinto, Florentia Peintinger, Ellen Schlichting, Lukas Dostalek, Helidon Nina, Hagigat Valiyeva Qanimat, Ashutosh Kothari, Marian Vanhoeij, Andraž Perhavec, Tsvetomir Ivanov, Douglas Zippel, Lía P. Rebaza, Sarun Thongvitokomarn, Bilge Aktas Sezen, Sarah Fröhlich, Tomasz Berger, Franziska Ruf, Angelika Rief, Esther Schmidt, Kristina Wihlfahrt, Timo Basali, Marc Thill, Michael P. Lux, Sibylle Loibl, Hans-Christian Kolberg, Toralf Reimer, Jens-Uwe Blohmer, Markus Hahn, Steffi Hartmann. AXSANA: Status of the international prospective multicenter cohort study evaluating different surgical methods of axillary staging in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy (NCT04373655) [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P2-10-25.