The Organgruppe Mamma der Arbeitsgemeinschaft Gynaekologische Onkologie (AGO) conducted a nationwide 3-phase analysis of the care structure and standard of therapy given to patients with breast cancer from 2002 (4th quarter) to 2004 (4th quarter). The analysis includes 1069 patients from 257 institutions; 34% with early breast cancer and 66% with metastatic disease. No reliable data on the pattern of care of these patients have been published to date in Germany. The extent to which national and international therapy recommendations were implemented in routine clinical practice was unclear. Evaluation of the data shows that treatment based on the guidelines is now being implemented very reliably in certain sectors. This is of particular relevance to the pattern of adjuvant treatment in early breast cancer. At that time 68 % of the patients received an anthracyclin based chemotherapy and in addition 18% received an anthracycline and taxane based chemotherapy. Participation in clinical trials peaked with 30% in the neoadjuvant setting. The problem with metastatic breast cancer is the complexity of the interdisciplinary treatment involved. The present analysis conducted by the AGO was the first attempt to analyse the treatment given to metastatic patients and to systematise the approach to treatment. The fundamental problem remains, irrespective of the stage of the tumour, namely that too few patients are treated in randomised clinical studies.