The Breast Commission of the German Gynecological Oncology Working Group AGO revises in annual intervals their evidence-based recommendations on therapy of primary and advanced breast cancer. A purely scientific assessment of the most recent published literature according to standardized level of evidence and grade of recommendation is supplemented by a newly developed AGO recommendation system which constitutes an expert consensus considering also clinical relevance, feasibility, and compliance. It is an approach of providing readers with an additional assessment trying to help them to select the most appropriate treatment for the individual patient situation. In the following, an overview is given on the most important aspects in diagnosis and therapy of metastatic breast cancer. For detailed aspects, a comprehensive set of slides including a more complete bibliography may be accessed under .