Necessity of chemotherapy
With approximately 72,000 new cases each year, breast cancer is the most common cancer among women in Germany. But breast cancer is not always the same thing, and thus each treatment should be based on an individual decision.
Crucial factors for the right choice of treatment are molecular markers such as hormone receptors and the growth factor receptor HER2/neu. Thus, the tumours can be divided into three subgroups important for diagnosis.
According to the current clinical guidelines, hormone receptor-negative (HR-) or HER2/neu-positive tumours are usually treated by chemotherapy, because this therapy is especially effective in the control of these two tumour subtypes. In patients with hormone receptor-positive and HER2/neu-negative breast cancer, the benefits of chemotherapy are often lower. This group includes some 65 % of patients.
The majority of these patients would be adequately treated with anti-hormonal therapy, whose side-effects are lower, but some do benefit from additional chemotherapy. Since the classical examination methods, however, do not allow clear judgement as to which treatment is most appropriate, as a precaution the majority of these patients are treated with chemotherapy. Thus many patients are over-treated.
Detailed analyses of the growth behaviour of a tumour at the genetic level have been included recently into the accepted guidelines (e.g. AGO, St. Gallen). The tests provide valuable additional information to select the therapy most appropriate for an individual patient. The only test of this kind that can be performed locally at the breast centres is EndoPredict.