Radiation Associated Cardiac Failure

The majority of early breast cancer patients are treated with adjuvant radiation therapy (RT) as part of their multimodal therapy. The aim of the RT is to lower the risk of local, regional and distant failure and improve survival. Modern RT is been provided with photon therapy. Now, more proton therapy facilities are opened, including in Denmark. Proton RT may have the potential to cause lower dose to heart and lung during breast RT. This trial will randomise patients between standard photon RT versus experimental proton RT. The primary endpoint is 10 year risk of heart disease.