Short Term Outcomes After PRoton And photoN radiOtherapy for IDH Mutated Grade 2 and 3 Gliomas

Study Overview
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Brief Summary
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Rationale: Proton beam therapy has recently become available for the treatment of patients with WHO grade 2 and 3 IDH mutated (IDHmt) glioma in the Netherlands. The dose distributions associated with proton therapy have substantially reduced the volume of the normal brain irradiated with low and intermediate radiotherapy doses. Whether this impacts rates of progressive disease or safety issues and how this compares with a similar population treated with photon therapy is currently unknown. Objective: To investigate short term outcomes after proton and photon radiotherapy for grade 2 and 3 IDHmt glioma.

Detailed Description
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Patients with grade 2 and 3 IDHmt glioma treated with proton therapy in Holland PTC, Maastro and UMC Groningen and referred Erasmus MC, Haaglanden MC, LUMC, Amsterdam UMC, Verbeeten Institute, Maastro, UMC Groningen, and Leuven University Hospital between 1st of January 2018 and the 30th of June 2022. The outcomes will be compared to those from patients with grade 2 and 3 IDHmt glioma treated with photon therapy in the same institutes and during the same period of time. The applied clinical target volume (CTV) margins and the chemotherapy are preferably similar for proton and photon therapy. Retrospective data will be collected from the electronic records of each participating institute. For the primary outcome, data will be collected on interventions (radiotherapy, surgery, chemotherapy, medication) for either tumor progression or toxicity after radiotherapy. This will be used to calculate next intervention free survival as primary outcome. For the secondary outcomes, data on survival, disease progression, pseudoprogression, and toxicity will be used to calculate overall survival, progression free survival, and pseudoprogression free survival, as well as toxicity incidence.

Official Title
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Short Term Outcomes After PRoton And photoN radiOtherapy for IDH Mutated Grade 2 and 3 Gliomas

Conditions
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Glioma, Radiotherapy; Complications

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Histopathologically confirmed WHO grade 2 or grade WHO 3 IDHmt glioma Treatment with radiotherapy delivered between 1 of January 2018 and completed before or on the 30th of June 2022 Treatment with chemotherapy delivered after radiotherapy (PCV or Temozolomide) Age ≥ 18 years Exclusion Criteria: Prior cranial radiotherapy Contra-indication for MRI imaging Chemotherapy delivered before radiotherapy Dose and fractionation other that standard dose (50.4 Gy in 28 fractions for Grade 2 and 59.5 Gy in 33 fractions for Grade 3) Combination photon and proton therapy Patient has previously opted-out of the use of their data for research

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Proton group<br>Patients with grade 2 and 3 IDHmt glioma treated with proton therapy in Holland PTC, Maastro and UMC Groningen. | |
| Photon group<br>Patients with grade 2 and 3 IDHmt glioma treated with photon therapy in Erasmus MC, Haaglanden MC, LUMC, Amsterdam UMC, Verbeeten Institute, Maastro, UMC Groningen, and Leuven University Hospital. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Next intervention-free survival | Time from the last day of radiotherapy until the start of a new next intervention. Next intervention is defined as either neurosurgical re-operation, re-irradiation, start of new chemotherapy (other than the standard adjuvant chemotherapy), start of VGEF inhibitors such as bevacizumab, or new start of dexamethasone for either tumor progression or radiotherapy effects. | 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Adverse Events | Assessed and scored based on the Common Terminology Criteria for Adverse Events (CTCAEv5.0). Only grade 3, 4 and 5 adverse events will be recorded. | 24 months | 
| Overall survival | Measured from the last day of radiotherapy to death from any cause | 24 months | 
| Progression-free survival | Time from the last day of radiotherapy until progressive disease | 24 months | 
| Pseudoprogression-free survival | time from the last day of radiotherapy and the development of any transient contrast-enhancing lesion between the end of radiotherapy and disease progression, or any new contrast-enhancing lesion that remained stable over a period of 12 months | 24 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Neuro-oncology, Proton therapy, Photon therapy