The Advanced Breast Cancer Fourth Consensus (ABC4) on diagnosis and treatment of advanced breast cancer (ABC) again took place in Lisbon, on November 2-4, 2017, and was chaired by Fatima Cardoso, MD, PhD. This year's contents focused very much on new developments in the treatment of ABC. For example, the significance of inhibition of cyclin-dependent kinases 4 and 6 (CDK4/6) in hormone receptor (HR)-positive ABC, of dual antibody blockade in human epidermal growth factor receptor 2 (HER2)-positive ABC, and of poly(ADP-ribose) polymerase (PARP) inhibition in triple-negative ABC, as well as the potential therapeutic consequences, were discussed. Other key issues were BRCA-associated breast cancer, treatment of brain metastases, and personalized therapy decision-making using molecular testing (so-called ‘precision medicine'). As in past years, an important objective of the ABC conference was cooperation with representatives of patient organizations from around the world. This cooperation was further intensified during the ABC4. Following the main conference, the ‘Global Alliance' was founded, with the goal of publicizing and coordinating measures necessary worldwide from the patient advocates' standpoint. - The ABC consensus inevitably cannot accommodate country-specific needs, due to the truly global expert panel. Therefore, a working group of German breast cancer experts commented - as in the past years - on the on-site voting results by the ABC panelists upon which the final ABC4 consensus will be based, with particular consideration of the German guidelines on diagnosis and treatment of breast cancer for everyday treatment in Germany.