The focus of this phase 2-trial is set on feasibility as well as early and late toxicity rates. One possible disadvantage of extreme hypofractionation could be an increased rate of fibrosis within the irradiated region. Therefore, a closer look will be taken with this prospective trial.~In addition, we are planning an accompanying translational research program since hypofractionated schedules are suggested to be more immunogenic in breast cancer.~Secondary objectives therefore are: cosmetic outcome, local tumor control, quality of life, dynamic immune status, importance of tumor infiltrating immune cells, overall survival, disease-free survival, feasibility of breath-hold radiation technique.
Evaluation of treatment toxicity of extreme hypofractionation of the whole breast in five fractions of 5.2 Gy in five consecutive workdays.