Abstract
Adjuvant radiotherapy is frequently used in women with breast cancer to improve both local control of the tumour and overall survival. Hypofractionated regimens are increasingly being used as they involve fewer treatment sessions and, in terms of tumour control, the effects of conventionally fractionated and hypofractionated radiotherapy seem to be comparable. However, there is concern regarding increased cardiotoxicity following hypofractionated radiotherapy treatment to the left side. In order to determine if cardiac mortality increases with hypofractionation relative to conventional fractionation, a Canadian research group performed a retrospective analysis in 5334 women with breast cancer treated between 1990-1998 with postoperative radiotherapy to the breast/chest wall only. At 15-year follow-up the authors concluded that cardiac mortality was not statistically different among patients with left-sided breast cancer whether treated with hypofractionated or conventionally fractionated whole breast/chest wall irradiation. This commentary discusses the data presented in the paper, puts them into perspective and describes the clinical implications.