Open Access

Steffi Hartmann, Maggie Banys-Paluchowski, Tomasz Berger, Nina Ditsch, Elmar Stickeler, Jana de Boniface, Oreste Davide Gentilini, Jennifer Schroth, Guldeniz Karadeniz Cakmak, Isabel T. Rubio, Maria Luisa Gasparri, Michalis Kontos, Eduard-Alexandru Bonci, Laura Niinikoski, Dawid Murawa, Geeta Kadayaprath, David Pinto, Florentia Peintinger, Ellen Schlichting, Lukas Dostalek, Helidon Nina, Hagigat Valiyeva, Marian Vanhoeij, Andraž Perhavec, Douglas Zippel, Lia Pamela Rebaza, Sarun Thongvitokomarn, Sarah Fröhlich, Franziska Ruf, Angelika Rief, Kristina Wihlfahrt, Timo Basali, Marc Thill, Michael Patrick Lux, Sibylle Loibl, Hans-Christian Kolberg, Jens-Uwe Blohmer, Markus Hahn, Meryem Gunay Gurleyik, Mauro Porpiglia, Semra Gunay, Linda Zetterlund, Thorsten Kuehn

• Introduction: Marking metastatic lymph nodes before neoadjuvant chemotherapy (NACT) has become increasingly popular in the surgical treatment of breast cancer. A variety of devices are currently in use. However, the significance of lost markers is poorly understood, and their impact on clinical decisions is unclear. Materials and methods: Among participants enrolled in the prospective AXSANA cohort study, those planned for target lymph node biopsy (TLNB) or targeted axillary dissection (TAD) with completed post-NACT locoregional therapy (surgery and radiotherapy) by January 21, 2025, were included. Results: In 88 of 1528 patients (5.8 %), axillary markers could not successfully be removed during surgery after NACT. The lost marker rate differed depending on the marker type (metallic clip/coil 7.0 %, carbon 3.1 %, radar reflector 1.4 %, magnetic seed 0.6 %, radioactive seed 0.0 %, p < 0.001). Additional postoperative imaging was performed in 25 (28.4 %) and further surgery toIntroduction: Marking metastatic lymph nodes before neoadjuvant chemotherapy (NACT) has become increasingly popular in the surgical treatment of breast cancer. A variety of devices are currently in use. However, the significance of lost markers is poorly understood, and their impact on clinical decisions is unclear. Materials and methods: Among participants enrolled in the prospective AXSANA cohort study, those planned for target lymph node biopsy (TLNB) or targeted axillary dissection (TAD) with completed post-NACT locoregional therapy (surgery and radiotherapy) by January 21, 2025, were included. Results: In 88 of 1528 patients (5.8 %), axillary markers could not successfully be removed during surgery after NACT. The lost marker rate differed depending on the marker type (metallic clip/coil 7.0 %, carbon 3.1 %, radar reflector 1.4 %, magnetic seed 0.6 %, radioactive seed 0.0 %, p < 0.001). Additional postoperative imaging was performed in 25 (28.4 %) and further surgery to remove axillary markers was performed in 6 (6.8 %) patients with lost markers. The proportion of patients undergoing axillary lymph node dissection (46.6 % versus 36.5 %, p 0.069) and axillary radiotherapy (51.1 % versus 50.2 %, p 0.748) did not differ between patients with and without lost markers. After an average follow-up of 21.8 months, axillary recurrences occurred in 3 patients (3.3 %) with and 16 patients (1.0 %) without lost markers (rate ratio 2.89, p 0.088). Conclusion: The loss of markers in TLNB/TAD is uncommon and significantly depends on the marking technique. Lost markers may lead to diagnostic uncertainties and additional imaging or surgical procedures.…