Clinical Investigation of Proton Treatment in Hodgkin Lymphoma Patients - PRO-Hodgkin

Inclusion Criteria: * Histological diagnosis of classic Hodgkin Lymphoma. * Ann Arbour stage 1A, 1B or 2A. * Both patients with and without risk factors, i.e. bulky disease, erythrocyte sedimentation rate (ESR)\>50, more than two involved sites. * Supra diaphragmal disease. * Age 18-60 years. * Eastern Cooperative Oncology Group (ECOG) performance status 0 - 2. * Initial staging positron emission tomography/computed tomography (PET/CT). * Induction chemotherapy including 2 cycles of ABVD for patients without risk factors and 4 cycles of ABVD for patients with risk factors. * For patients with risk factors a CT after 2 ABVD confirming complete remission (CR) or partial remission (PR). For patients without risk factors clinical response is sufficient at inclusion, but a CT scan is recommended before start of radiotherapy. * Radiotherapy (RT) start not later than 6 weeks after end of chemotherapy. * Written informed consent obtained prior to any study specific procedures. * Women of reproductive age must agree to use contraceptives during the study treatment period. Exclusion Criteria: * Pregnancy. * Serious concomitant systemic disorder endangering treatment delivery. * More than 5mm tumour motion on 4 dimensional computed tomography (4DCT) unless deep inspiration breath hold (DIBH) is used. Not applicable if target is located outside mediastinum or photon treatment is planned. * Clinical or radiographic stable disease (SD)/ progressive disease (PD) during induction chemotherapy. * Not able to comply with treatment and study procedures. * No additional active malignancy except indolent lymphoma in the bone marrow, basal cell carcinoma of the skin, squamous cell carcinoma of the skin or in situ cervical cancer.