This review summarises the potential usage of proton therapy in Denmark. About one third of Danes are diagnosed with cancer, and half of these need radiotherapy in the course of treatment. Radiation dose cannot be adequately increased without giving rise to unacceptable, high risk of toxicity, but proton therapy is encouraging due to a unique depth dose distribution. In some cases, the benefit of proton therapy is obvious, but in most cases the gain is less obvious, and patients should only receive treatment within clinical trials. Clinical studies on proton therapy with focus on reduction of radiation-induced side effects and improvement of quality of life should be conducted.