In early stage breast cancer, radiotherapy (RT) is generally given in the adjuvant setting after surgery (postoperative RT or postop RT). However, a recent retrospective study in breast cancer patients showed that preoperative (preop) RT might improve disease free survival compared to postop RT(1). In another retrospective study comparing neoadjuvant versus adjuvant radiochemotherapy a possible benefit of neoadjuvant treatment was suggested for tumours larger than 2 cm (2). From a radiobiological point of view, the benefits of giving RT preoperatively are not surprising. In contrast to the postop setting, the vasculature is still intact as less radioresistant tumour clones are present, both possibly increasing radiosensitivity. But there are other advantages of preop RT treatment. There is a possibility of downsizing the tumour which might lead to a lower need for mastectomy and target volume delineation for RT planning is easier since the tumour is still in place. For the latter reason, less acute side effects and a better overall breast cosmesis is expected.