Surgical staging procedures of the axilla in initially clinically node-positive (cN +) breast cancer patients receiving neoadjuvant chemotherapy (NACT) vary across countries. Different procedures such as axillary lymph node dissection, sentinel lymph node biopsy, target lymph node biopsy and targeted axillary dissection are currently in use. To date, data on radar reflectors as a non-wire and non-radioactive technique for marking target lymph nodes are limited. The present study aims at examining the detection rate, the rate of lost markers, and magnetic resonance imaging artifacts after TLN marking using a radar reflector before NACT in the largest available cohort of breast cancer patients enrolled in the international prospective AXSANA study. AXSANA (EUBREAST-03) is an international prospective cohort study including cN + patients managed with different surgical axillary staging techniques after NACT. Eligible patients have cT1-4c cN + breast cancer and receive neoadjuvant chemotherapy. Patients are followed up for 5 years. In the present subgroup analysis, only patients with a TLN marked by a radar reflector were included. A TLN was marked by radar reflector insertion in 158 patients prior to NACT. Of these, 136 had final surgery results available at the time of analysis, and in 135 out of these 136 patients, localization of TLN was attempted. All radar markers were successfully removed. While lymphoid tissue corresponding to the TLN was identified in 132 patients (97.8

BACKGROUND:Assessing the axillary response to neoadjuvant chemotherapy (NACT) in patients with initially node-positive breast cancer is crucial to determine the most appropriate surgical approach. While axillary ultrasound (AUS) is a well-established tool in the upfront surgery setting, its performance after NACT is still questioned. Here, we assess the reliability of AUS in predicting the pathological axillary status after NACT using data from the large prospective multicenter AXSANA trial. METHODS:Between June 1, 2020, and May 31, 2024, 5.559 patients were enrolled in the AXSANA trial. For this analysis, patients with clinically node-positive breast cancer who underwent AUS after NACT were eligible. AUS`s sensitivity, specificity, positive (PPV) and negative predictive value (NPV) were analyzed using surgical staging as reference. FINDINGS:3840 patients were eligible for this analysis. Of these, 3428(89.3 %) patients underwent preoperative AUS after NACT, classified as unclear in 168(4.9 %), positive in 1060(30.9 %) and negative in 2200 (64.2 %). An axillary pathological complete response (pCR) was achieved in 1793(55.0 %). Nodal metastases were detected in 786 of 2200 patients (35.7 %) with an negative AUS, while 379(35.8 %) of 1060 patients with a positive AUS achieved an axillary pCR. AUS sensitivity was 46.4 %(95 % CI 43.8 %-49.0 %), specificity 78.9 %(76.9 %-80.7 %), PPV 64.2 %(61.3 %-67.1 %), and NPV 64.3 %(62.2 %-66.3 %). PPV was highest for HR+ /HER2- tumors (81.9 %, 78.9 %-85.2 %), NPV for HR-/HER2 + tumors (88.3 %, 84.2 %-91.7 %). Triple negative and HER2 + subtypes were significantly less frequently associated with false-negative AUS results than an HR+ /HER2- cancer. INTERPRETATION:AUS alone does not reliably predict pathological nodal status. Axillary lymph node dissection based on positive AUS findings after NACT results in surgical overtreatment. Surgical axillary staging after NACT remains essential for the accurate assessment of axillary lymph node status in patients with initially node-positive breast cancer.

Background: In the last decades, the proportion of breast cancer patients receiving breast-conserving surgery has increased, reaching 70-80% in developed countries. In case of non-palpable lesions, surgical excision requires some form of breast localization. While wire-guided localization has long been considered gold standard, it carries several limitations, including logistical difficulties, the potential for displacement and patient discomfort, and re-excision rates reaching 21%. Other techniques (radioactive seed or radio-occult lesion localization, intraoperative ultrasound, magnetic, radiofrequency and radar localization) have been developed with the aim of overcoming these disadvantages. However, comparative data on the rates of successful lesion removal, negative margins and re-operations are limited. In the majority of studies, the patient’s perspective with regard to discomfort and pain level has not been evaluated. The aim of MELODY (MEthods for LOcalization of Different types of breast lesions) is to evaluate different imaging-guided localization methods with regard to oncological safety, patient-reported outcomes, and surgeon and radiologist satisfaction. Methods: The EUBREAST and the iBRA-NET have initiated the MELODY study to assess breast localization techniques and devices from several perspectives (NCT05559411, http://melody.eubreast.com). MELODY is a prospective intergroup cohort study which enrolls female and male patients requiring breast-conserving surgery and image-guided localization for invasive breast cancer or DCIS. Multiple or bilateral lesions and neoadjuvant chemotherapy are allowed. Primary outcomes are: 1) Intended target lesion and/or marker removal, independent of margin status on final histopathology, and 2) Negative resection margin rates at first surgery. Secondary outcomes are, among others: rates of second surgery and secondary mastectomy, Resection Ratio (defined as actual resection volume divided by the calculated optimum specimen volume), duration of surgery, marker dislocation rates, rates of marker placement or localization failure, comparison of patient-reported outcomes, rates of “lost markers” and diagnostician/radiologist’s and surgeon’s satisfaction as well as the health economic evaluation of the different techniques. Target accrual: 7,416 patients. Enrollment started in January 2023. The study is being conducted in 30 countries and is supported by the Oncoplastic Breast Consortium (OPBC), AWOgyn, AGO-B and SENATURK. Financial support was provided by Endomag, Merit Medical, Sirius Medical and Hologic. Citation Format: Maggie Banys-Paluchowski, Nina Ditsch, Thorsten Kühn, James Harvey, Nuh Zafer Canturk, Neslihan Cabioglu, Tove Filtenborg Tvedskov, Lina Pankratjevaite, Maria Luisa Gasparri, Dawid Murawa, Jai Min Ryu, Oreste Davide Gentilini, Rosa Di Micco, Mah Muneer Khan, Aoife Lowery, Natalia Krawczyk, Steffi Hartmann, Isabel T. Rubio, Antonio J. Esgueva, Jana de Boniface, Andreas Karakatsanis, Rajiv V. Dave, Shelley Potter, Ashutosh Kothari, Walter Paul Weber, Güldeniz Karadeniz Cakmak, Markus Hahn, Michael Patrick Lux, Marjolein Smidt, Bahadir M. Gulluoglu, Michaelis Kontos, Florentina Peintinger, Lia Pamela Rebaza, Maria Antónia Vasconcelos, Mariana Correia, Sarah Nietz, Francois Malherbe, Severine Alran, Khaled Mohammad Abdelwahab, Veronica Yamila Fabiano, Svs Deo, Yazan Masannat, Katharina Jursik, Bilge Aktas Sezen, Meldoy Study Group. MELODY: A prospective non-interventional multicenter cohort study to evaluate different imaging-guided methods for localization of malignant breast lesions (EUBREAST-4 / iBRA-NET, NCT 05559411) [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 P3-12-16.

503 Background: Surgical axillary staging in patients with node-positive (cN+) breast cancer scheduled for neoadjuvant chemotherapy (NACT) varies significantly, and includes axillary lymph node dissection (ALND), sentinel lymph node biopsy (SLNB), targeted axillary dissection (TAD), and target lymph node biopsy (TLNB). SLNB/TAD/TLNB aim at reducing surgical morbidity without loosing staging accuracy. Comparative data on marking techniques for TAD/TLNB are limited. Here, different marking techniques from the largest available international prospective cohort are critically evaluated. Methods: AXSANA is an ongoing cohort study investigating oncological and patient-reported outcomes after different axillary procedures in cN+ breast cancer treated with NACT. In the present analysis, the subgroup of patients receiving marking of their TLN is selected, and detection and removal rates are analyzed. The entire dataset is continuously and systematically monitored for data quality assurance. Results: 6,129 patients from 291 sites in 26 countries were included between June 2020 and January 6 th , 2025. Of these, 2,596 had ≥ 1 TLN marked before NACT and had completed surgery at time of analysis. The mean number of suspicious nodes at diagnosis was 1.9 (≥ 4 in 13.4%). 2,484 patients (95.7%) received a minimally invasive biopsy of ≥ 1 node. TLN marking was performed using a clip in 2,003 patients (77.2%), a magnetic seed in 287 (11.1%), carbon ink in 192 (7.4%), radar marker in 119 (4.6%), radioactive seed in 18 (0.7%), radiofrequency identification device (RFID) in 12 (0.5%) or other methods in 2 (0.1%). > 1 type of marker was placed in 36 patients (1.4%). 1 TLN was marked in 2,427 patients (93.5%), followed by 2 TLNs in 138 (5.3%) and ≥ 3 in 27 patients (1%). The mean number of marked TLNs was highest if carbon ink was used (mean 1.21), followed by clip (1.07), magnetic seed (1.06) and radar marker (1.04); no patient received > 1 radioactive seed/RFID. 1,895 patients (73.0%) achieved ycN0 status. Targeted removal of the TLN was planned in 2,100 patients (80.9%): 2,076 (80.0%) were scheduled for a TAD and 24 (0.9%) for a TLNB. TLN was detected and removed during TAD/TLNB in 1,915 patients (91.2%). TLN detection rate was highest in patients whose TLNs were marked with probe-guided techniques (96.6%; radioactive seed: 100%, magnetic seed: 96.9%, radar marker: 96.1%, RFID: 90%), followed by carbon (94.9%) and clip (89.6%; p < 0.001). TAD/TLNB removed a median number of 3 nodes (mean 4.1, SD 2.77; carbon: median 4, mean 4.29, SD 3.52, probe-guided: median 3, mean 3.82, SD 2.63, clip: median 3, mean 4.15, SD 2.75). Conclusions: This large prospective analysis of patients with initially cN+ breast cancer receiving NACT demonstrates that probe-guided markers provide superior TLN detection rates. Clinical trial information: NCT04373655 .

PURPOSE We assessed the accuracy and reproducibility of Chat Generative Pre-Trained Transformer's (ChatGPT) recommendations in response to breast cancer patients by comparing generated outputs with consensus expert opinions. METHODS 362 consecutive breast cancer patients sourced from a weekly international breast cancer webinar series were submitted to a tumor board of renowned experts. The same 362 clinical patients were also prompted to ChatGPT-4.0 three separate times to examine reproducibility. RESULTS Only 46% of ChatGPT-generated content was entirely concordant with the recommendations of breast cancer experts, and only 39% of ChatGPT's responses demonstrated inter-response similarity. ChatGPT's responses demonstrated higher concordance with CEN experts in earlier stages of breast cancer (0, I, II, III) compared to advanced (IV) patients ( P = .019). There were less accurate responses from ChatGPT when responding to patients involving molecular markers and genetic testing ( P = .025), and in patients involving antibody drug conjugates ( P = .006). ChatGPT's responses were not necessarily incorrect but often omitted specific details about clinical management. When the same prompt was independently sent to CEN into the model on three occasions, each time by difference users, ChatGPT's responses exhibited variable content and formatting in 68% (246 out of 362) of patients and were entirely consistent with one another in only 32% of responses. CONCLUSION Since this promising clinical decision-making support tool is widely used currently by physicians worldwide, it is important for the user to understand its limitations as currently constructed when responding to multidisciplinary breast cancer patients, and for researchers in the field to continue improving its ability with contemporary, accurate and complete breast cancer information. As currently constructed, ChatGPT is not engineered to generate identical outputs to the same input and was less likely to correctly interpret and recommend treatments for complex breast cancer patients.

Background: Breast cancer (BC) is the most frequent type of cancer in women worldwide. Evidence-based follow-up strategies regarding risk, patients’ needs and quality of life are lacking. The main objectives of this study are to determine the range and prevalence of physical, psychological and social problems following breast cancer treatment, and to identify patterns of physical, psychological and social problems based on demographic and clinical factors. Methods: The EORTC 1617-QLG-BCG-ROG is an international cross-sectional non-interventional follow-up study in patients who are disease-free at least 1 but no more than 3 years since completion of primary treatment (except hormonal treatment) for early BC (EBC) and locally advanced BC (LABC). Institutional, demographic, tumour and treatment history data were collected. Patients completed a PRO questionnaire set once including the EORTC QLQ-C30, QLQ-BR45, EORTC QLQ-SHQ-22, EORTC QLQ-OUT-PATSAT-7, one question regarding follow up strategy from the patient´s point of view, and the Distress Thermometer, 139 items in total. A total of 830 patients would allow adequate estimation of prevalence rates and 90% power to detect a 10% difference between two cohorts. Patients were stratified by age, NPI risk score and treatment to ensure adequate representation within each stratum. Results: Between November 2020 and September 2022, a total of 833 patients were enrolled in 25 institutions (of which 17 had a dedicated breast unit) across 10 countries. Of these 833 patients, 686 (82%) had EBC and 144 (17%) LABC. A total of 805 (97%) questionnaires set were completed, either in whole or partially, by eligible patients. More than 60% reported maximal score on the role and social functioning scale, as well as 50% reported no symptoms on nausea/vomiting, diarrhoea, insomnia, appetite loss and constipation. Regarding stage of the disease, EBC patients showed statistically significant better (at 1% level of significance) scores in the physical functioning, role functioning, and cognitive functioning scales of EORTC C30 compared to the patients with LABC. Regarding age, young patients ( < 50y) showed statistically significant worse scores in emotional functioning, cognitive functioning, social functioning, fatigue, and insomnia and reported more financial difficulties compared to the older population. Regarding type of therapy, patients receiving chemotherapy showed statistically significant worse scores in the physical functioning, role functioning, cognitive functioning, social functioning, fatigue, nausea/vomiting, pain, and financial difficulty scales, compared to the patients without chemotherapy even though the therapy had ended 1 to 3 years before. Further analyses of EORTC QLQ-BR45, EORTC QLQ-SHQ 22, and EORTC QLQ-OUT-PATSAT7 including comparison with normative data, are currently being performed and will be presented at SABCS 2024. Conclusions: Patients with EBC and LABC showed a distinct increase in physical functioning, role functioning, and cognitive functioning scales during follow-up after completion of primary treatment. Results showed that especially young patients and patients received chemotherapy are vulnerable groups, even after the end of therapy. These problems were associated with cognitive functioning, social functioning, fatigue, and financial difficulty. Information gained from this study will be useful for refining follow-up programs in EBC and LABC. Citation Format: Vesna Bjelic-Radisic, Katarzyna Pogoda, Helen Westenberg, Samantha Serpentini, Hikmat Abdel-Razeq, Joanna Kazmierska, Thomas Kuhnt, Eva Fernandez Lizarbe, Elisabetta Cretella, Icro Meattini, Frederieke van Duijnhoven, Isabel Teresa Rubio, Razvan Popescu, Sue Hartrup, Heidi Roelstraete, Nora Nevries, Corneel Coens, Melanie Beauvois, Luisi Lim, Galina Velikova, David Cameron, Fatima Cardoso. Follow-up in Early and Locally Advanced Breast Cancer Patients: An EORTC QLG-BCG- ROG study [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 P2-01-08.

AIMS:We investigated factors related to the type of surgery, i.e. mastectomy versus breast conserving surgery (BCS), in breast cancer (BC) patients with complete pathologic response in the breast (ypT0) after neoadjuvant therapy (NAT). METHODS:A retrospective analysis from the EUSOMA database was performed using data from 55 certified centers across 14 European countries, including ypT0 BC patients (i.e., neither invasive nor in situ residuals), treated between 2017 and 2022. Variables analyzed included year of surgery, age, number and distribution of tumor focality, extent, clinical and pathological stages, and biologic subtype. Logistic regression was used to identify predictors of surgical choice. The Kaplan-Meier method was used for comparison of local recurrence-free survival (LRFS) between surgical groups. RESULTS:Of 1416 BC patients included, 67.5 % underwent BCS and 32.5 % mastectomy. At multivariable analysis, factors increasing the likelihood of mastectomy included: more recent year of surgery [odds ratio (OR) 2.61, 95 % confidence interval (95%CI): 1.51-4.51,p = 0.001], younger age (OR: 0.96, 95%CI: 0.95-0.97,p < 0.001), multifocality (OR: 2.20, 95%CI: 1.61-3.00,p < 0.001) and multicentricity (OR: 12.66, 95%CI: 6.82-23.49,p < 0.001), advanced clinical tumor stage (OR: 14.54, 95%CI: 5.80-36.47,p < 0.001), and baseline axillary nodal involvement (OR: 1.56, 95%CI: 1.12-2.17,p = 0.009). Comparison between groups did not show a significant difference in LRFS (p = 0.389). CONCLUSION:Many BC patients undergo mastectomy despite achieving complete response of primary tumor after NAT. Patients-related and tumor-related features, as well as having surgery in more recent years, seems to influence this choice. Our findings suggest the need for an optimized decision-making to spare unnecessary mastectomies.

PURPOSE:Genomic testing, involving expression profiling of tumour tissue, is a powerful tool for determining appropriate treatments for certain cancer patients. This study aimed to evaluate awareness of genomic testing in breast cancer patients in five European countries. METHODS:The survey was initiated by Cancer Patients Europe and developed with patient associations, oncologists, and a psycho-oncologist. Participants were recruited via email and social media and completed a 42-question internet survey. RESULTS:Of 1383 participants in eligible countries completing the survey, 566 women with current or previous HR+/HER2- breast cancer, potentially eligible for genomic testing, were analysed. 245 (43.3 %) were aged 50-59 years and 381 (67.3 %) had received higher education. 238 participants (42.1 %) had heard about genomic testing; 122 (21.6 %) were informed of their eligibility for testing, and 104 (18.4 %) were given reasons for the test. The majority (N = 479; 84.6 %) felt they lacked sufficient information to decide, and only 139 (24.6 %) opted for testing. Overall, 246 (43.5 %) wanted more information on additional testing and 234 (41.3 %) wanted more information on treatment options. The main information sources were medical professionals (N = 363; 64.1 %) and the internet (N = 351; 62.0 %). However, 398 participants (70.3 %) indicated that their healthcare professionals did not advise them on where to find more information. CONCLUSIONS:This study highlights insufficient awareness of, and access to, genomic testing in breast cancer. Healthcare professionals need to improve communication with patients regarding genomic testing and involve them in shared decision-making. Likewise, patient associations have a role in providing clear information to patients.

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 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.

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.