Improvements in multimodal therapy have resulted in high curation rates in lymphoma patients. In addition, these cancer entities (Hodgkin lymphoma and non-Hodgkin lymphoma) often affect very young patients. Due to the high healing rates, the long-term effects of therapy are increasingly coming into focus: more than 40% of patients suffer from chronic, therapy-associated secondary diseases 30 years after successful therapy [1]. For this reason, an important focus of current research is the reduction of therapy-associated toxicity. A certain trend of dose reduction and reduction of the radiation fields (involved-field, involved-node, involved-site radiation) can already be seen in the research results of the last decades. Another interesting approach to protecting adjacent organs is the use of modern radiation techniques such as particle therapy with protons (PT).~In the case of radiation in the mediastinal area in particular, the use of PT can greatly reduce the dose in the area of the heart muscle, the lungs or the mammary gland tissue compared to conventional radiation with photons. It is hoped that this will result in a decrease, especially in chronic side effects, in the area of these organs. Since this is a group of young patients with intensive pre-treatment with chemotherapeutic agents, a reduction in long-term toxicities is of particular importance. In particular, cardiac and pulmonary long-term side effects as well as a reduction in the secondary malignancy rate play a major role in this collective.~The aim of this prospective registry study on proton radiotherapy for mediastinal lymphomas is to record the frequency, feasibility and side effects after PT in this group of patients. These data should then serve as the basis for concrete therapy recommendations and assessment of side effects. Close cooperation with the study groups should also enable a comparative analysis of comparable patients who were not treated with protons at a later point in time.
The aim is to record and document a mediastinal PT and the corresponding follow-up data (effectiveness and side effects). General recommendations for planning and feasibility are made within the framework of this study.