Biomarkers are integral to modern breast cancer management by providing essential information for prognosis and treatment selection. This review presents the 2026 update of the recommendations of the Arbeitsgemeinschaft Gynäkologische Onkologie (German Gynecological Oncology Group, AGO) on therapy-relevant prognostic and predictive biomarkers. The recommendations are based on a structured evaluation of the most recent and clinically relevant evidence using the AGO grading system to support decision-making in routine clinical practice.

The German Guideline Committee (AGO: Working Group on Gynecologic Cancers) updated its yearly recommendations on the diagnosis and treatment of breast cancer in March 2026. Chapters on oncological and oncoplastic-reconstructive surgery are coordinated with the Working Group for Plastic, Aesthetic, and Reconstructive Surgery in Gynecology (AWOgyn). The most important changes include the ommission of sentinel lymph node biopsy (SLNB) and preffered axillary staging in patients with node-positive breast cancer undergoing neoadjuvant chemotherapy (NACT). Targeted axillary dissection (TAD) is endorsed as the method of choice [AGO ++] in patients converting from cN + to ycN0 status, and other de-escalated techniques (SLNB, target lymph node biopsy [TLNB]) are also possible options [AGO +]. Following NACT, ALND is indicated only when macrometastatic disease is detected in the sentinel and/or in the target lymph node.

The Breast Committee of the Arbeitsgemeinschaft Gynäkologische Onkologie (German Gynecological Oncology Group, AGO) presents the 2026 update of the evidence-based recommendations for the diagnosis and treatment of patients with locally advanced and metastatic breast cancer.

Patients with hormone receptor‐positive (HRpos), HER2‐negative (HER2neg) breast cancer (BC) benefit less from neoadjuvant chemotherapy (NACT) than patients with triple‐negative and HER2‐positive BC. In this retrospective analysis of the phase IV PreFace clinical trial (NCT01908556), where postmenopausal HRpos BC patients ( n = 3297) were treated with 5‐year upfront adjuvant letrozole therapy, we evaluated the prognosis of patients treated with adjuvant versus neoadjuvant chemotherapy in HRpos/HER2neg early‐stage BC. HRpos/HER2neg patients with information on (neo)adjuvant chemotherapy ( n = 2895) were retrospectively selected from all patients enrolled in the PreFace trial. Invasive disease‐free survival (iDFS) and overall survival (OS) were compared between patient groups that were treated with neoadjuvant or adjuvant chemotherapy. Chemotherapy was given to 1051 patients (36.3% of all patients), of which 874 (83.2%) received adjuvant chemotherapy and 177 (16.8%) NACT. Pathologic complete response (pCR) rate in the NACT group was 6.9%. Patients treated with NACT had a worse outcome than those treated with adjuvant chemotherapy (5‐year iDFS rate 81% vs. 88%; 5‐year OS rate 89% vs. 93%). This effect was maintained after adjusting for age, BMI, lymph node status, grading, tumor size, and histology (hazard ratio for iDFS: 1.95 (95%CI: 1.28–2.95); hazard ratio for OS: 2.13 (95%CI: 1.24–3.66)). Further adjustment for taxane‐based regimes did not alter results. In conclusion, in this retrospective analysis of patients with early‐stage HRpos/HER2neg BC, patients with NACT had a more unfavorable prognosis than patients treated adjuvantly, independent of patient and tumor characteristics. Prognosis of neoadjuvant patients might be affected by resistance mechanisms, warranting further investigation.

The German Guideline Commission (AGO: Working Group on Gynecologic Cancers) updated its recommendations on the diagnosis and treatment of breast cancer in March 2025. Chapters on oncological and oncoplastic-reconstructive surgery are coordinated with the Working Group for Plastic, Aesthetic, and Reconstructive Surgery in Gynecology (AWOgyn). The most important changes include the incorporation of INSEMA and SOUND trial results into the guidelines. In patients with low-risk characteristics, defined as age ≥50 years, postmenopausal status, hormone receptor-positive/HER2-negative subtype, tumor grading G1-2 with a maximum preoperative size of 2 cm, and unsuspicious axillary ultrasound and clinical examination, the sentinel lymph node biopsy (SLNB) can be omitted if breast-conserving surgery and whole-breast irradiation are planned. In patients with 1-2 macrometastatic sentinel lymph nodes (SLNs) undergoing a mastectomy and postoperative irradiation, completion axillary lymph node dissection (ALND) is no longer recommended. After neoadjuvant systemic therapy (NST), ALND is recommended if the targeted axillary dissection (TAD) shows macrometastases in the sentinel and/or in the target lymph node (the node that was marked and had a macrometastasis in the biopsy before NST). Patients with isolated tumor cells in the sentinel and/or target lymph node should not receive ALND after NST. In case of ypN1mi status, the decision to perform a completion ALND should be made on a case-by-case basis. Oncoplastic surgery is safe and may replace a mastectomy in select cases.

The Breast Committee of the Arbeitsgemeinschaft Gynäkologische Onkologie (German Gynecological Oncology Group, AGO) presents the 2025 update of the evidence-based recommendations for the diagnosis and treatment of patients with early breast cancer.

BACKGROUND:The optimal adjuvant endocrine treatment in premenopausal patients with hormone receptor-positive, HER2-negative (HRpos/HER2neg) early breast cancer (eBC) remains debated, particularly the choice between aromatase inhibitors plus ovarian function suppression (AI + OFS) or tamoxifen (TAM) with or without additional OFS. This study assessed the use of adjuvant endocrine therapies for premenopausal patients with intermediate/high-risk HRpos/HER2neg eBC. METHODS:CLEAR-B (AGO-B-059; NCT05870813) was a retrospective study analyzing data, collected from January 2016 to June 2019 and from January 2022 to December 2023 during the certification process of breast centers in Germany. Premenopausal patients with HRpos/HER2neg intermediate/high-risk eBC were eligible. Patient and disease characteristics, in addition to recommended and received adjuvant treatments, were evaluated. RESULTS:The number of registered patients was 3137, of whom 2789 had complete information on endocrine treatments (1717 for 2016-2019 and 1072 for 2022-2023). In 2016-2019, 8.4 % of the patients were recommended to be treated with AI + OFS, whereas in 2022-2023, the proportion of patients with a treatment recommendation for AI + OFS rose to 42.1 %. In 2016-2019, TAM monotherapy was most frequently recommended (80.8 %). Conversely, TAM + OFS was not commonly recommended (9.3 % in 2016-2019 and 16.5 % in 2022-2023). While no clear association between tumor stage and chosen endocrine therapy was found in 2016-2019, most patients with ≥stage IIA were recommended to be treated with AI + OFS in 2022-2023. CONCLUSION:This analysis shows that treatment recommendation for AI + OFS in premenopausal patients with HRpos/HER2neg eBC increased relevantly in the past years, reflecting latest guideline recommendations.

The Breast Committee of the Arbeitsgemeinschaft Gynäkologische Onkologie (AGO; German Gynecological Oncology Group) presents the 2025 update of the evidence-based recommendations for the diagnosis and treatment of patients with locally advanced and metastatic breast cancer (mBC).

Introduction: Each year the interdisciplinary AGO (Arbeitsgemeinschaft Gynäkologische Onkologie, German Gynecological Oncology Group) Breast Committee on Diagnosis and Treatment of Breast Cancer provides updated state-of-the-art recommendations for early and metastatic breast cancer. Methods: The updated evidence-based treatment recommendations for early and metastatic breast cancer have been released in March 2024. Results and Conclusion: This paper concisely captures the updated recommendations for early breast cancer chapter by chapter.

The Breast Committee of the Arbeitsgemeinschaft Gynäkologische Onkologie (German Gynecological Oncology Group, AGO) presents the 2024 update of the evidence-based recommendations for the diagnosis and treatment of patients with locally advanced and metastatic breast cancer.

Background The monarchE and NATALEE trials demonstrated the benefit of CDK4/6 inhibitor (CDK4/6i) therapy in adjuvant breast cancer (BC) treatment. Patient selection, based on clinical characteristics, delineated those at high (monarchE) and high/intermediate recurrence risk (NATALEE). This study employed a historical patient cohort to describe the proportion and prognosis of patients eligible for adjuvant CDK4/6i trials. Methods Between 2009 and 2011, 3529 patients were enrolled in the adjuvant PreFace clinical trial (NCT01908556). Eligibility criteria included postmenopausal patients with hormone receptor-positive (HRpos) BC for whom a five-year upfront therapy with letrozole was indicated. Patients were categorized into prognostic groups according to monarchE and NATALEE inclusion criteria, and their invasive disease-free survival (iDFS) and overall survival (OS) were assessed. Results Among 2891 HRpos patients, 384 (13.3%) met the primary monarchE inclusion criteria. The majority (n=261) qualified due to having ≥4 positive lymph nodes. For NATALEE, 915 out of 2886 patients (31.7%) met the eligibility criteria, with 126 patients (13.7%) being node-negative. Patients from monarchE with ≥4 positive lymph nodes and NATALEE with stage III BC exhibited the poorest prognosis (3-year iDFS rate 0.87). Patients ineligible for the trials demonstrated prognoses similar to the most favorable patient groups within the eligibility criteria. Conclusion Patient populations eligible for monarchE and NATALEE trials differed. Nearly a third of the postmenopausal HRpos population, previously under upfront letrozole treatment, met the NATALEE prognostic eligibility criteria. As certain eligible groups had a prognosis similar to non-eligible patients, it might be interesting to explore additional patient groups for CDK4/6i therapy.

The Breast Committee of the Arbeitsgemeinschaft Gynäkologische Onkologie (German Gynecological Oncology Group, AGO) presents the 2023 update of the evidence-based recommendations for the diagnosis and treatment of patients with locally advanced and metastatic breast cancer (mBC).

Importance The increasing use of neoadjuvant systemic therapy (NST) has led to substantial pathological complete response rates in patients with initially node-positive, early breast cancer, thereby questioning the need for axillary lymph node dissection (ALND). Targeted axillary dissection (TAD) is feasible for axillary staging; however, data on oncological safety are scarce. Objective To assess 3-year clinical outcomes in patients with node-positive breast cancer who underwent TAD alone or TAD with ALND. Design, Setting, and Participants The SenTa study is a prospective registry study and was conducted between January 2017 and October 2018. The registry includes 50 study centers in Germany. Patients with clinically node-positive breast cancer underwent clipping of the most suspicious lymph node (LN) before NST. After NST, the marked LNs and sentinel LNs were excised (TAD) followed by ALND according to the clinician’s choice. Patients who did not undergo TAD were excluded. Data analysis was performed in April 2022 after 43 months of follow-up. Exposure TAD alone vs TAD with ALND. Main Outcomes and Measures Three-year clinical outcomes were evaluated. Results Of 199 female patients, the median (IQR) age was 52 (45-60) years. A total of 182 patients (91.5%) had 1 to 3 suspicious LNs; 119 received TAD alone and 80 received TAD with ALND. Unadjusted invasive disease-free survival was 82.4% (95% CI, 71.5-89.4) in the TAD with ALND group and 91.2% (95% CI, 84.2-95.1) in the TAD alone group ( P = .04); axillary recurrence rates were 1.4% (95% CI, 0-54.8) and 1.8% (95% CI, 0-36.4), respectively ( P = .56). Adjusted multivariate Cox regression indicated that TAD alone was not associated with an increased risk of recurrence (hazard ratio [HR], 0.83; 95% CI, 0.34-2.05; P = .69) or death (HR, 1.07; 95% CI, 0.31-3.70; P = .91). Similar results were obtained for 152 patients with clinically node-negative breast cancer after NST (invasive disease-free survival: HR, 1.26; 95% CI, 0.27-5.87; P = .77; overall survival: HR, 0.81; 95% CI, 0.15-3.83; P = .74). Conclusions and Relevance These results suggest that TAD alone in patients with mostly good clinical response to NST and at least 3 TAD LNs may confer survival outcomes and recurrence rates similar to TAD with ALND.

Zusammenfassung Die Empfehlungen der AGO-Kommission Mamma zur operativen Therapie des Mammakarzinoms wurden zuletzt im März 2022 aktualisiert (www.ago-online.de). Da die operative Therapie einen von mehreren Teilschritten bei der Behandlung des Mammakarzinoms darstellt, sind eine umfangreiche diagnostische und onkologische Expertise eines Brustoperateurs und eine gute interdisziplinäre Zusammenarbeit mit den diagnostischen Radiologen von großer Bedeutung. Die wichtigsten Änderungen betreffen die Lokalisationstechniken, die Resektionsränder, das axilläre Management im neoadjuvanten Setting und die Bewertung der Netze in der rekonstruktiven Chirurgie. Aufgrund von Metanaanalysen randomisierter Studien wurde der Empfehlungsgrad der intraoperativen Mammasonografie zur Lokalisation nicht palpabler Befunde auf „++“ erhöht. Somit wird die Technik als gleichwertig zur Drahtlokalisation angesehen, vorausgesetzt, es handelt sich um eine sonografisch gut darstellbare Läsion, der Operateur verfügt über umfangreiche Kenntnisse in der Mammasonografie und hat Zugang zu einem geeigneten Ultraschallgerät während der Operation. Beim invasiven Mammakarzinom wird das Erreichen von negativen Resektionsrändern („no tumor on ink“) angestrebt, unabhängig davon, ob eine extensive intraduktale Komponente vorliegt oder nicht. Onkoplastische Operationen können durch die Vielzahl der existierenden Techniken in ausgewählten Fällen auch eine Mastektomie ersetzen und sind im Vergleich zu einer regulären Segmentresektion hinsichtlich der onkologischen Sicherheit bei vergleichbaren Komplikationsraten gleichwertig. Patientinnen mit cN0-Status, die eine neoadjuvante Chemotherapie erhalten, wird eine Sentinel-Node-Exzision nach Abschluss der Chemotherapie empfohlen. Bei initial suspekten Lymphknoten wird die minimalinvasive Sicherung empfohlen. Nach der neoadjuvanten Chemotherapie stehen Patientinnen mit initial 1–3 suspekten Lymphknoten und gutem Ansprechen (ycN0) die „Targeted axillary Dissection“ und die Axilladissektion als gleichwertige Optionen zur Verfügung.

The Breast Committee of the Arbeitsgemeinschaft Gynakologische Onkologie (German Gynecological Oncology Group, AGO) presents the 2022 update of the evidence-based recommendations for the diagnosis and treatment of patients with locally advanced and metastatic breast cancer. (C) 2022 S. Karger AG, Basel

The Breast Committee of the Arbeitsgemeinschaft Gynäkologische Onkologie (German Gynecological Oncology Group, AGO) presents the 2022 update of the evidence-based recommendations for the diagnosis and treatment of patients with locally advanced and metastatic breast cancer.

Zusammenfassung Über viele Jahrzehnte war die komplette Ausräumung der axillären Lymphknoten im Sinne einer Axilladissektion ein Standardverfahren in der Therapie des Mammakarzinom. Die Zielsetzung lag in der Bestimmung des histologischen Nodalstatus für die Festlegung der adjuvanten Therapie sowie in der Sicherung der lokoregionären Tumorkontrolle. Neben der Diskussion zur Optimierung der Therapiestrategien in der systemischen Behandlung und in der Strahlentherapie fokussieren aktuelle Diskussionen insbesondere auch auf die Verbesserung der chirurgischen Maßnahmen beim Mammakarzinom. Unter Berücksichtigung der zunehmenden Bedeutung der neoadjuvanten Chemotherapie erfährt die operative Behandlung des Mammakarzinoms sowohl im Bereich der Brust als auch im Bereich der Achselhöhle einen Wandel. Basierend auf der derzeitigen Datenlage wird die SLNE vor einer neoadjuvanten Chemotherapie grundsätzlich nicht empfohlen. Demgegenüber wird die operative axilläre Intervention – von der SLNE über die TAD bis zur ALND – nach der neoadjuvanten Chemotherapie als Vorgehen der Wahl zum axillären Staging angesehen. Zur Verringerung der Falsch-negativ-Rate des operativen Stagings der Axilla bei pN+CNB vor NACT und ycN0 nach NACT sind Targeted axillary Dissection (TAD), die Entfernung von > 2 SLNs (SLNE, kein ungezieltes axilläres Sampling), die Immunhistochemie zur Detektion von isolierten Tumorzellen oder Mikrometastasen und die Markierung von positiven Lymphknoten vor NACT als Standard anzusehen. In dem aktuellen Update zur operativen axillären Intervention wird auf die Bedeutung von isolierten Tumorzellen und Mikrometastasen nach neoadjuvanter Chemotherapie und die klinischen Konsequenzen einer mittels SLNE und TAD diagnostizierten Low Volume residual Disease eingegangen und ein Überblick bez. der diesjährigen AGO-Empfehlungen zum operativen Management der Axilla im Rahmen der Primäroperation und im Zusammenhang mit der neoadjuvanten Chemotherapie gegeben.

Introduction: The AGO (Arbeitsgemeinschaft Gynäkologische Onkologie, German Gynecological Oncology Group) Task Force on Diagnosis and Treatment of Breast Cancer as an interdisciplinary team consists of specialists from gynecological oncology, pathology, diagnostic radiology, medical oncology, and radiation oncology with a special focus on breast cancer. Methods: The updated evidence-based treatment recommendation 2022 for early breast cancer (EBC) and metastatic breast cancer of the AGO Task Force has been released. Results and Conclusion: This paper captures the update of EBC.

The recommendations of the AGO Breast Committee on the surgical therapy of breast cancer were last updated in March 2022 (www.ago-online.de). Since surgical therapy is one of several partial steps in the treatment of breast cancer, extensive diagnostic and oncological expertise of a breast surgeon and good interdisciplinary cooperation with diagnostic radiologists is of great importance. The most important changes concern localization techniques, resection margins, axillary management in the neoadjuvant setting and the evaluation of the meshes in reconstructive surgery. Based on meta-analyses of randomized studies, the level of recommendation of an intraoperative breast ultrasound for the localization of non-palpable lesions was elevated to "++". Thus, the technique is considered to be equivalent to wire localization, provided that it is a lesion which can be well represented by sonography, the surgeon has extensive experience in breast ultrasound and has access to a suitable ultrasound device during the operation. In invasive breast cancer, the aim is to reach negative resection margins ("no tumor on ink"), regardless of whether an extensive intraductal component is present or not. Oncoplastic operations can also replace a mastectomy in selected cases due to the large number of existing techniques, and are equivalent to segmental resection in terms of oncological safety at comparable rates of complications. Sentinel node excision is recommended for patients with cN0 status receiving neoadjuvant chemotherapy after completion of chemotherapy. Minimally invasive biopsy is recommended for initially suspect lymph nodes. After neoadjuvant chemotherapy, patients with initially 1 - 3 suspicious lymph nodes and a good response (ycN0) can receive the targeted axillary dissection and the axillary dissection as equivalent options.