Proton Therapy for Mediastinal Lymphoma (PROMLY)

Patients are referred for proton therapy based on a reduction of risk of late toxicity which is established on consensus guidelines and multidisciplinary discussions in a study panel/consensus conference. However, this reduction is calculated based on the referring center's treatment planning scan and patient setup.

The aim of this national study is to investigate whether the calculated reduction of risk of toxicity with proton therapy at the referring centers differs from the actual delivered plan at DCPT (ΔNTCP in delivered proton therapy plan versus reference photon plan from referring center).

The study also aims to investigate effect and side effects of proton and photon radiotherapy, including a systematically prospective registration of acute and late side effects and to evaluate the use of a model-based approach to select patients for proton therapy.

• Proton therapy (Radiation): If selected, patients will recieve protontherapy instead of photon therapy

Primary outcomes

• Correlation between ΔNTCP_expected and ΔNTCP_delivered. [From enrollment to end of radiotherapy, average 5 weeks.]: The correlation between ΔNTCP_expected and ΔNTCP_delivered, is an investigation to see whether the ΔNTCP (ΔNTCP_expected) calculated from the planning CT from the refering center, correlates with the ΔNTCP from the actual delivered plan (ΔNTCP_delivered) at the Danish Centre for Particle Therapy.

Secondary outcomes

• Incidence of acute, late toxicity and other events [From enrollment to 20 years after end of radiation]: A) Acute toxicity 1. Radiation dermatitis 2. Cough 3. Fatigue 4. Dysphagia Add a 2nd Outcome Measure B) Incidence of: 1. secondary cancers (breast and lung) 2. other secondary cancers within the radiation field. 3. Myocardial infarction 4. Other cardiac events Add a 3rd Outcome Measure C) Overall survival Add a 4th Outcome Measure D) Recurrence free survival

Other outcomes

• Radiation dosimetry [From enrollment to 20 years after end of radiotherapy]: Data from the study will be compared between 1\) Patients treated with protons vs patients treated with photons. 2) Data from the study compared to Historical data. 3) NTCP estimated risk vs. actual events (protons and photons).

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Patients 18 years or older
* Histologically proven Hodgkin or non-Hodgkin lymphoma
* Disease constrained within the mediastinum +/- neck and/or axilla involvement.
* Candidates for curative intended treatment
* Signed written informed consent.

Exclusion Criteria:

* Prior radiotherapy to the thorax
* Other current malignancy
* Inability to attend full course of radiotherapy or follow-up visits in the outpatient clinic.