Joint EANM-SNMMI guideline on the role of 2-[18F]FDG PET/CT in no special type breast cancer : (endorsed by the ACR, ESSO, ESTRO, EUSOBI/ESR, and EUSOMA).

INTRODUCTION: There is much literature about the role of 2-[18F]FDG PET/CT in patients with breast cancer (BC). However, there exists no international guideline with involvement of the nuclear medicine societies about this subject. PURPOSE: To provide an organized, international, state-of-the-art, and multidisciplinary guideline, led by experts of two nuclear medicine societies (EANM and SNMMI) and representation of important societies in the field of BC (ACR, ESSO, ESTRO, EUSOBI/ESR, and EUSOMA). METHODS: Literature review and expert discussion were performed with the aim of collecting updated information regarding the role of 2-[18F]FDG PET/CT in patients with no special type (NST) BC and summarizing its indications according to scientific evidence. Recommendations were scored according to the National Institute for Health and Care Excellence (NICE) criteria. RESULTS: Quantitative PET features (SUV, MTV, TLG) are valuable prognostic parameters. In baseline staging, 2-[18F]FDG PET/CT plays a role from stage IIB through stage IV. When assessing response to therapy, 2-[18F]FDG PET/CT should be performed on certified scanners, and reported either according to PERCIST, EORTC PET, or EANM immunotherapy response criteria, as appropriate. 2-[18F]FDG PET/CT may be useful to assess early metabolic response, particularly in non-metastatic triple-negative and HER2+ tumours. 2-[18F]FDG PET/CT is useful to detect the site and extent of recurrence when conventional imaging methods are equivocal and when there is clinical and/or laboratorial suspicion of relapse. Recent developments are promising. CONCLUSION: 2-[18F]FDG PET/CT is extremely useful in BC management, as supported by extensive evidence of its utility compared to other imaging modalities in several clinical scenarios.

Locoregional Breast Cancer Recurrence in the European Organisation for Research and Treatment of Cancer 10041/BIG 03-04 MINDACT Trial: Analysis of Risk Factors Including the 70-Gene Signature.

PURPOSE: A number of studies are currently investigating de-escalation of radiation therapy in patients with a low risk of in-breast relapses on the basis of clinicopathologic factors and molecular tests. We evaluated whether 70-gene risk score is associated with risk of locoregional recurrence (LRR) and estimated 8-year cumulative incidences for LRR in patients with early-stage breast cancer treated with breast conservation. METHODS: In this exploratory substudy of European Organisation for Research and Treatment of Cancer 10041/BIG 03-04 MINDACT trial, we evaluated women with a known clinical and genomic 70-gene risk score test result and who had breast-conserving surgery (BCS). The primary end point was LRR at 8 years, estimated by cumulative incidences. Distant metastasis and death were considered competing risks. RESULTS: Among 6,693 enrolled patients, 5,470 (81.7%) underwent BCS, of whom 98% received radiotherapy. At 8-year follow-up, 189 patients experienced a LRR, resulting in an 8-year cumulative incidence of 3.2% (95% CI, 2.7 to 3.7). In patients with a low-risk 70-gene signature, the 8-year LRR incidence was 2.7% (95% CI, 2.1 to 3.3). In univariable analysis, adjusted for chemotherapy, five of 12 variables were associated with LRR, including the 70-gene signature. In multivariable modeling, adjuvant endocrine therapy and to a lesser extent tumor size and grade remained significantly associated with LRR. CONCLUSION: This exploratory analysis of the MINDACT trial estimated an 8-year low LRR rate of 3.2% after BCS. The 70-gene signature was not independently predictive of LRR perhaps because of the low number of events observed and currently cannot be used in clinical decision making regarding LRR. The overall low number of events does provide an opportunity to design trials toward de-escalation of local therapy.

EUSOMA quality indicators for non-metastatic breast cancer: An update.

INTRODUCTION: Quality care in breast cancer is higher if patients are treated in a Breast Center with a dedicated and specialized multidisciplinary team. Quality control is an essential activity to ensure quality care, which has to be based on the monitoring of specific quality indicators. Eusoma has proceeded with the up-dating of the 2017 Quality indicators for non-metastatic breast cancer based on the new diagnostic, locoregional and systemic treatment modalities. METHODS: To proceed with the updating, EUSOMA setup a multidisciplinary working group of BC experts and patients' representatives. It is a comprehensive set of QIs for early breast cancer care, which are classified as mandatory, recommended, or observational. For the first time patient reported outcomes (PROMs) have been included. As used in the 2017 EUSOMA QIs, evidence levels were based on the short version of the US Agency for Healthcare Research and Quality. RESULTS: This is a set of quality indicators representative for the different steps of the patient pathway in non-metastatic setting, which allow Breast Centres to monitor their performance with referring standards, i.e minimum standard and target. CONCLUSIONS: Monitoring these Quality Indicators, within the Eusoma datacentre will allow to have a state of the art picture at European Breast Centres level and the development of challenging research projects.

European guidelines for the diagnosis, treatment and follow-up of breast lesions with uncertain malignant potential (B3 lesions) developed jointly by EUSOMA, EUSOBI, ESP (BWG) and ESSO.

INTRODUCTION: Breast lesions of uncertain malignant potential (B3) include atypical ductal and lobular hyperplasias, lobular carcinoma in situ, flat epithelial atypia, papillary lesions, radial scars and fibroepithelial lesions as well as other rare miscellaneous lesions. They are challenging to categorise histologically, requiring specialist training and multidisciplinary input. They may coexist with in situ or invasive breast cancer (BC) and increase the risk of subsequent BC development. Management should focus on adequate classification and management whilst avoiding overtreatment. The aim of these guidelines is to provide updated information regarding the diagnosis and management of B3 lesions, according to updated literature review evidence. METHODS: These guidelines provide practical recommendations which can be applied in clinical practice which include recommendation grade and level of evidence. All sections were written according to an updated literature review and discussed at a consensus meeting. Critical appraisal by the expert writing committee adhered to the 23 items in the international Appraisal of Guidelines, Research and Evaluation (AGREE) tool. RESULTS: Recommendations for further management after core-needle biopsy (CNB) or vacuum-assisted biopsy (VAB) diagnosis of a B3 lesion reported in this guideline, vary depending on the presence of atypia, size of lesion, sampling size, and patient preferences. After CNB or VAB, the option of vacuum-assisted excision or surgical excision should be evaluated by a multidisciplinary team and shared decision-making with the patient is crucial for personalizing further treatment. De-escalation of surgical intervention for B3 breast lesions is ongoing, and the inclusion of vacuum-assisted excision (VAE) will decrease the need for surgical intervention in further approaches. Communication with patients may be different according to histological diagnosis, presence or absence of atypia, or risk of upgrade due to discordant imaging. Written information resources to help patients understand these issues alongside with verbal communication is recommended. Lifestyle interventions have a significant impact on BC incidence so lifestyle interventions need to be suggested to women at increased BC risk as a result of a diagnosis of a B3 lesion. CONCLUSIONS: These guidelines provide a state-of-the-art overview of the diagnosis, management and prognosis of B3 lesions in modern multidisciplinary breast practice.

Global Cancer Surgery: pragmatic solutions to improve cancer surgery outcomes worldwide.

The first Lancet Oncology Commission on Global Cancer Surgery was published in 2015 and serves as a landmark paper in the field of cancer surgery. The Commission highlighted the burden of cancer and the importance of cancer surgery, while documenting the many inadequacies in the ability to deliver safe, timely, and affordable cancer surgical care. This Commission builds on the first Commission by focusing on solutions and actions to improve access to cancer surgery globally, developed by drawing upon the expertise from cancer surgery leaders across the world. We present solution frameworks in nine domains that can improve access to cancer surgery. These nine domains were refined to identify solutions specific to the six WHO regions. On the basis of these solutions, we developed eight actions to propel essential improvements in the global capacity for cancer surgery. Our initiatives are broad in scope, pragmatic, affordable, and contextually applicable, and aimed at cancer surgeons as well as leaders, administrators, elected officials, and health policy advocates. We envision that the solutions and actions contained within the Commission will address inequities and promote safe, timely, and affordable cancer surgery for every patient, regardless of their socioeconomic status or geographic location.

Intraoperative ultrasound margin evaluation as a tool to reduce positive superficial margins in nipple and skin sparing mastectomy in breast cancer patients.

BACKGROUND: Intraoperative ultrasound (IOUS) guided conservative surgery has been shown to reduce rates of positive margins in breast cancer. The aim of the study is to evaluate the feasibility of using IOUS to assess superficial/anterior margins in nipple and skin sparing mastectomy (NSM/SSM) and its impact on reducing rates of positive margins. METHODS: This prospective study includes all breast cancer patients who had an indication for NSM/SSM at our Institution. Superficial margin width was measured by IOUS before surgery and the area marked on the skin. Same measurement was performed afterwards in the mastectomy specimen. Any superficial margin < 5 mm was re-excised intraoperatively following the mark on the skin. RESULTS: Fifty-nine patients were included, 47 patients (79.7%) underwent NSM, and 12 patients (20.3%) a SSM. Of the 59 patients, 23 (38.98%) had margins ≥5 mm and 36 patients (61.02%) had margins of ≤5 mm. Of the 36 patients with superficial margins ≤5 mm, 20 had margins <2 mm, and 6 of them had intraoperative involved superficial margins in final pathology. However, after IOUS-guided re-excision, final pathology showed no involved margins. A 2 mm margin was set as the cut-off point for performing an intraoperative re-excision. IOUS guided re-excisions for intraoperative margins ≤2 mm significantly reduced the risk of close/positive margins in final pathology, p < 0.0001. CONCLUSION: The results showed that IOUS margin evaluation significantly reduced the rate of superficial positive margins in NSM/SSM. It is feasible and effective and may avoid challenging reoperations and/or additional radiation therapy for positive margins.

The Lucerne Toolbox 2 to optimise axillary management for early breast cancer: a multidisciplinary expert consensus.

Clinical axillary lymph node management in early breast cancer has evolved from being merely an aspect of surgical management and now includes the entire multidisciplinary team. The second edition of the "Lucerne Toolbox", a multidisciplinary consortium of European cancer societies and patient representatives, addresses the challenges of clinical axillary lymph node management, from diagnosis to local therapy of the axilla. Five working packages were developed, following the patients' journey and addressing specific clinical scenarios. Panellists voted on 72 statements, reaching consensus (agreement of 75% or more) in 52.8%, majority (51%-74% agreement) in 43.1%, and no decision in 4.2%. Based on the votes, targeted imaging and standardized pathology of lymph nodes should be a prerequisite to planning local and systemic therapy, axillary lymph node dissection can be replaced by sentinel lymph node biopsy ( ± targeted approaches) in a majority of scenarios; and positive patient outcomes should be driven by both low recurrence risks and low rates of lymphoedema.

Trends and variation in treatment of early breast cancer in European certified breast centres: an EUSOMA-based analysis.

BACKGROUND: Practice indicators (PI) measure provided care making use of real-world data. This study describes trends and variations in adjuvant treatment of early breast cancer (EBC) using the European Society of Breast Cancer Specialists (EUSOMA) database. METHODS: The analysis was conducted on anonymous cumulative data registered by 56 certified breast centres, which all entered at least 500 new diagnoses in the database in the 10-year period 2010-2019. Practice trends of radiotherapy, endocrine treatment, chemotherapy, and anti-HER2 therapy were evaluated. The association with age group (<50, 50-69, ≥70) and geographical area of the centre (Northern, Central, Southern Europe; NE, CE, SE) was assessed with the Pearson Chi2 test for independence in contingency tables. RESULTS: In total, 150,150 patients with EBC were selected. Overall, radiotherapy was administered more frequently in NE centres, and conversely, endocrine, chemo-, and anti-HER2 therapy were used more frequently in SE centres (p<0.001). 46.9% of the pN1 patients received postmastectomy radiotherapy, with significant differences by age and geographical region (p < 0.001). Adjuvant endocrine treatment for endocrine-sensitive carcinoma in situ was administered in 46.1%, with a decreasing trend during the study period (58.5-34.5%; p < 0.001). Anti-HER2 therapy was delivered in 75.6% of all patients with HER2BC T1a/bN0, patients older than 70 received anti-HER2 in 67.6% in SE compared to 31.3% in NE centres. CONCLUSION: Important variations in EBC management between European certified breast centres have been demonstrated. PI using real-world data can help to monitor, evaluate, and eventually guide and align good clinical practice in the management of breast cancer.

European Society of Breast Cancer Specialists/Advanced Breast Cancer Global Alliance quality indicators for metastatic breast cancer care.

AIMS: Improvement in the care of patients with metastatic breast cancer (MBC) can only occur if the adequate quality of care is implemented and verified, including access to multidisciplinary, specialised care given in accordance with high-quality guidelines. To this purpose, European Society of Breast Cancer Specialists and the Advanced Breast Cancer Global Alliance joined efforts to develop the first set of quality indicators (QI) specifically for MBC that should be routinely measured and evaluated to ensure that breast cancer centres meet the required standards. METHODS: A working group of multidisciplinary European experts in breast cancer met to discuss each identified QI, reporting the definition, the minimum and target standard for breast cancer centres to achieve, and the motivation for selection. The level of evidence was determined according to the short version of the United States Agency for Healthcare Research and Quality classification. RESULTS: QI to measure access to and involvement in multidisciplinary and supportive care, appropriate pathological characterisation of disease, systemic therapies and radiotherapy were developed with the consensus of the working group. CONCLUSIONS: This is the first effort of a multistep project that aims to have QI for MBC routinely measured and evaluated to ensure that breast cancer centres achieve mandated standards in the care of patients with metastatic disease.

Feasibility and safety of targeted axillary dissection guided by intraoperative ultrasound after neoadjuvant treatment.

BACKGROUND: Axillary management in cN + axillary nodes after neoadjuvant systemic therapy (NST) in breast cancer (BC) remains under research with the aim of de-escalation of axillary node dissection (ALND). Several axillary guided localization techniques have been reported. This study evaluates the safety of intraoperative ultrasound (IOUS) guided targeted axillary dissection (TAD) in a large sample after the results of ILINA trial. MATERIALS: Prospective data have been collected from October 2015 to June 2022 in patients with cT0-T4 and positive axillary lymph nodes (cN1) treated with NST. Before NST, an ultrasound visible marker was placed into the positive node. After NST, IOUS guided TAD was performed including sentinel node biopsy (SLN). Until December 2019, all patients underwent an ALND after TAD procedure. From January 2020, ALND was spared in those patients with an axillary pathological complete response (pCR). RESULTS: 235 patients were included. pCR (ypT0/is ypN0) was achieved in 29% patients. Identification rate (IR) of the clipped node by IOUS was 96% (95% IC, 92.5-98.1%) and IR of SLN was 95% (95% IC, 90.8-97.2%). False negative rate (FNR) for TAD procedure (SLN + clipped node) was 7.0% (95% IC, 2.3-15.7%), which decreased to 4.9% when a total of 3 or more nodes were removed. Axillary ultrasound before surgery assessed residual disease with an AUC of 0.5241. Residual axillary disease tend to be the most significant factor for axillary recurrences. CONCLUSIONS: This study confirms the feasibility, safety and accuracy of IOUS guided surgery for axillary staging after NST in node positive BC patients.

Uncertainties and controversies in axillary management of patients with breast cancer.

The aims of this Oncoplastic Breast Consortium and European Breast Cancer Research Association of Surgical Trialists initiative were to identify uncertainties and controversies in axillary management of early breast cancer and to recommend appropriate strategies to address them. By use of Delphi methods, 15 questions were prioritized by more than 250 breast surgeons, patient advocates and radiation oncologists from 60 countries. Subsequently, a global virtual consensus panel considered available data, ongoing studies and resource utilization. It agreed that research should no longer be prioritized for standardization of axillary imaging, de-escalation of axillary surgery in node-positive cancer and risk evaluation of modern surgery and radiotherapy. Instead, expert consensus recommendations for clinical practice should be based on current evidence and updated once results from ongoing studies become available. Research on de-escalation of radiotherapy and identification of the most relevant endpoints in axillary management should encompass a meta-analysis to identify knowledge gaps, followed by a Delphi process to prioritize and a consensus conference to refine recommendations for specific trial designs. Finally, treatment of residual nodal disease after surgery was recommended to be assessed in a prospective register.

Real de-escalation or escalation in disguise?

The past two decades have seen an unprecedented trend towards de-escalation of surgical therapy in the setting of early BC, the most prominent examples being the reduction of re-excision rates for close surgical margins after breast-conserving surgery and replacing axillary lymph node dissection by less radical procedures such as sentinel lymph node biopsy (SLNB). Numerous studies confirmed that reducing the extent of surgery in the upfront surgery setting does not impact locoregional recurrences and overall outcome. In the setting of primary systemic treatment, there is an increased use of less invasive staging strategies reaching from SLNB and targeted lymph node biopsy (TLNB) to targeted axillary dissection (TAD). Omission of any axillary surgery in the presence of pathological complete response in the breast is currently being investigated in clinical trials. On the other hand, concerns have been raised that surgical de-escalation might induce an escalation of other treatment modalities such as radiation therapy. Since most trials on surgical de-escalation did not include standardized protocols for adjuvant radiotherapy, it remains unclear, whether the effect of surgical de-escalation was valid in itself or if radiotherapy compensated for the decreased surgical extent. Uncertainties in scientific evidence may therefore lead to escalation of radiotherapy in some settings of surgical de-escalation. Further, the increasing rate of mastectomies including contralateral procedures in patients without genetic risk is alarming. Future studies of locoregional treatment strategies need to include an interdisciplinary approach to integrate de-escalation approaches combining surgery and radiotherapy in a way that promotes optimal quality of life and shared decision-making.

EBCC-13 manifesto: Balancing pros and cons for contralateral prophylactic mastectomy.

After a diagnosis of unilateral breast cancer, increasing numbers of patients are requesting contralateral prophylactic mastectomy (CPM), the surgical removal of the healthy breast after diagnosis of unilateral breast cancer. It is important for the community of breast cancer specialists to provide meaningful guidance to women considering CPM. This manifesto discusses the issues and challenges of CPM and provides recommendations to improve oncological, surgical, physical and psychological outcomes for women presenting with unilateral breast cancer: (1) Communicate best available risks in manageable timeframes to prioritise actions; better risk stratification and implementation of risk-assessment tools combining family history, genetic and genomic information, and treatment and prognosis of the first breast cancer are required; (2) Reserve CPM for specific situations; in women not at high risk of contralateral breast cancer (CBC), ipsilateral breast-conserving surgery is the recommended option; (3) Encourage patients at low or intermediate risk of CBC to delay decisions on CPM until treatment for the primary cancer is complete, to focus on treating the existing disease first; (4) Provide patients with personalised information about the risk:benefit balance of CPM in manageable timeframes; (5) Ensure patients have an informed understanding of the competing risks for CBC and that there is a realistic plan for the patient; (6) Ensure patients understand the short- and long-term physical effects of CPM; (7) In patients considering CPM, offer psychological and surgical counselling before surgery; anxiety alone is not an indication for CPM; (8) Eliminate inequality between countries in reimbursement strategies; CPM should be reimbursed if it is considered a reasonable option resulting from multidisciplinary tumour board assessment; (9) Treat breast cancer patients at specialist breast units providing the entire patient-centred pathway.

European Groundshot-addressing Europe's cancer research challenges: a Lancet Oncology Commission.

Cancer research is a crucial pillar for countries to deliver more affordable, higher quality, and more equitable cancer care. Patients treated in research-active hospitals have better outcomes than patients who are not treated in these settings. However, cancer in Europe is at a crossroads. Cancer was already a leading cause of premature death before the COVID-19 pandemic, and the disastrous effects of the pandemic on early diagnosis and treatment will probably set back cancer outcomes in Europe by almost a decade. Recognising the pivotal importance of research not just to mitigate the pandemic today, but to build better European cancer services and systems for patients tomorrow, the Lancet Oncology European Groundshot Commission on cancer research brings together a wide range of experts, together with detailed new data on cancer research activity across Europe during the past 12 years. We have deployed this knowledge to help inform Europe's Beating Cancer Plan and the EU Cancer Mission, and to set out an evidence-driven, patient-centred cancer research roadmap for Europe. The high-resolution cancer research data we have generated show current activities, captured through different metrics, including by region, disease burden, research domain, and effect on outcomes. We have also included granular data on research collaboration, gender of researchers, and research funding. The inclusion of granular data has facilitated the identification of areas that are perhaps overemphasised in current cancer research in Europe, while also highlighting domains that are underserved. Our detailed data emphasise the need for more information-driven and data-driven cancer research strategies and planning going forward. A particular focus must be on central and eastern Europe, because our findings emphasise the widening gap in cancer research activity, and capacity and outcomes, compared with the rest of Europe. Citizens and patients, no matter where they are, must benefit from advances in cancer research. This Commission also highlights that the narrow focus on discovery science and biopharmaceutical research in Europe needs to be widened to include such areas as prevention and early diagnosis; treatment modalities such as radiotherapy and surgery; and a larger concentration on developing a research and innovation strategy for the 20 million Europeans living beyond a cancer diagnosis. Our data highlight the important role of comprehensive cancer centres in driving the European cancer research agenda. Crucial to a functioning cancer research strategy and its translation into patient benefit is the need for a greater emphasis on health policy and systems research, including implementation science, so that the innovative technological outputs from cancer research have a clear pathway to delivery. This European cancer research Commission has identified 12 key recommendations within a call to action to reimagine cancer research and its implementation in Europe. We hope this call to action will help to achieve our ambitious 70:35 target: 70% average 10-year survival for all European cancer patients by 2035.

Evolution and refinement of magnetically guided sentinel lymph node detection in breast cancer: meta-analysis.

BACKGROUND: Superparamagnetic iron oxide nanoparticles (SPIO) have been used as a tracer for sentinel lymph node (SLN) localization in breast cancer, demonstrating comparable performance to the combination of radioisotope (RI) and blue dye (BD). METHODS: A systematic literature search and meta-analysis with subgroup and meta-regression analysis were undertaken to update the available evidence, assess technique evolution, and define knowledge gaps. Recommendations were made using the GRADE approach. RESULTS: In 20 comparative studies, the detection rate was 97.5 per cent for SPIO and 96.5 per cent for RI ± BD (risk ratio 1.006, 95 per cent c.i. 0.992 to 1.019; P = 0.376, high-certainty evidence). Neoadjuvant therapy, injection site, injection volume or nodal metastasis burden did not affect the detection rate, but injection over 24 h before surgery increased the detection rate on meta-regression. Concordance was 99.0 per cent and reverse concordance 97.1 per cent (rate difference 0.003, 95 per cent c.i. -0.009 to 0.015; P = 0.656, high-certainty evidence). Use of SPIO led to retrieval of slightly more SLNs (pooled mean 1.96 versus 1.89) with a higher nodal detection rate (94.1 versus 83.5 per cent; RR 1.098, 1.058 to 1.140; P < 0.001; low-certainty evidence). In meta-regression, injection over 24 h before surgery increased the SPIO nodal yield over that of RI ± BD. The skin-staining rate was 30.8 per cent (very low-certainty evidence), and possibly prevented with use of smaller doses and peritumoral injection. CONCLUSION: The performance of SPIO is comparable to that of RI ± BD. Preoperative injection increases the detection rate and nodal yield, without affecting concordance. Whether skin staining and MRI artefacts are reduced by lower dose and peritumoral injection needs to be investigated.

How to improve efficiency in cancer care: Dimensions, methods, and areas of evaluation.

Efficiency in healthcare is crucial since available resources are scarce, and the cost of inefficient allocation is measured in prior outcomes. This is particularly relevant for cancer. The aim of this paper is to gain a comprehensive overview of the areas and dimensions to improve efficiency, and establish the indicators, different methods, perspectives, and areas of evaluation, to provide recommendations for how to improve efficiency and measure gains in cancer care. METHODS: We conducted a two-phase design. First, a comprehensive scoping literature review was conducted, searching four databases. Studies published between 2000 and 2021 were included if they described experiences and cases of efficiency in cancer care or methods to evaluate efficiency. The results of the literature review were then discussed during two rounds of online consultation with a panel of 15 external experts invited to provide insight and comments to deliberate policy recommendations. RESULTS: 46 papers met the inclusion criteria. Based on the papers retrieved we identified six areas for achieving efficiency gains throughout the entire care pathway and, for each area of efficiency, we categorized the methods and outcomes used to measure efficiency gain. CONCLUSION: This is the first attempt to systemize a scattered body of literature on how to improve efficiency in cancer care and identify key areas of improvement. POLICY SUMMARY: There are many opportunities to improve efficiency in cancer care. We defined seven policy recommendations on how to improve efficiency in cancer care throughout the care pathway and how to improve the measurement of efficiency gains.

Axillary surgery after neoadjuvant therapy in initially node-positive breast cancer: international EUBREAST survey.

BACKGROUND: There is no consensus on axillary management after neoadjuvant therapy (NAT) in patients with clinically node-positive (cN+) breast cancer. To investigate current clinical practice, an international survey was conducted among breast surgeons and radiation oncologists. The aim of the first part of the survey was to provide a snapshot of international discrepancies regarding axillary surgery in this context. METHODS: The European Breast Cancer Research Association of Surgical Trialists (EUBREAST) developed a web-based survey containing 39 questions describing clinical scenarios in the setting of axillary management in patients with cN1 disease converting to ycN0 after NAT. The survey was then distributed to breast surgeons and radiation oncologists via 14 breast cancer societies between April and October 2021. RESULTS: Responses from 349 physicians in 45 countries were recorded. The most common post-NAT axillary surgery in patients with cN1 disease converting to ycN0 was targeted axillary dissection (54.2 per cent), followed by sentinel lymph node biopsy (SLNB) alone (20.9 per cent), level 1-2 axillary lymph node dissection (ALND) (18.4 per cent), level 1-3 ALND (4 per cent), and targeted lymph node biopsy (2.5 per cent). For SLNB alone, dual tracers were most commonly used (62.3 per cent). Management varied widely in patients with ambiguous axillary status before initiation of treatment or a residual metastatic burden in the axilla after NAT. In patients with ycN+ tumours, ALND was the preferred surgical approach for 66.8 per cent of respondents. CONCLUSION: These results highlight the wide heterogeneity in surgical approaches to the axilla after NAT. To standardize the guidelines, further data from clinical research are urgently needed, which underlines the importance of the ongoing AXSANA (EUBREAST-3) study.