[Systemic treatment of breast cancer: professional guideline]

Since the III. Breast Cancer Consensus Conference, a number of new evidence based on clinical trial results have been published which justified updating the 2016 recommendation. In addition to classical prognostic factors, some multigenic tests, which we have incorporated into the recommendation, will play an important role in therapeutic decision-making. The professional guide primarily reflects the resolutions and recommendations of the current ESMO, NCCN, ABC4, as well as the St. Gallen Consensus Conference. From a didactic point of view, the text follows first the line of early and then locally advanced breast cancer, locoregionally recurrent and metastatic breast cancer. Within these, we discuss each group according to therapeutic options.