8th International consensus guidelines for the management of advanced breast cancer (ABC8 guidelines)

The Advanced Breast Cancer (ABC) 8th international consensus conference took place on 6-8 November 2025, in Lisbon, and updated the previous ABC international consensus guidelines that are described in this manuscript. These guidelines reflect the work of a large and global consensus panel, comprising healthcare professionals and patients, and provide recommendations on how to best manage patients with advanced breast cancer (inoperable locally advanced or metastatic), of all breast cancer subtypes. The guidelines are based on the best available evidence or on expert opinion when a higher level of evidence is lacking and aim to cover the needs of the person living with ABC, including but also beyond the main therapeutic recommendations. Each guideline is accompanied by the level of evidence (LoE), the grade of recommendation (GoR), and the percentage of consensus reached at the consensus session. Updated diagnostic and treatment algorithms are also provided. These guidelines are endorsed by several international oncology organizations (AGO, AORTIC, ECO, EONS, ESO, ESTRO, EUSOMA, GECO Perú, SUMA, MASCC, French Breast Cancer Guidelines and AMAAC) and have official representation from ASCO, NCCN and ABC-NZ. Inequalities in access to high-quality care have increased in the last decade, both between and within countries, and are a major concern. The ABC guidelines provide guidance on the best available management options for patients living with ABC globally, assuming availability of the recommended therapies. Their adaptation is often needed in resource-constrained settings, and the grading of each recommendation may help in prioritizing access to available options.