PRO-GLIO: PROton Versus Photon Therapy in IDH-mutated Diffuse Grade II and III GLIOmas

Proton therapy is a powerful tool enabling oncologists to spare normal tissue around the target for irradiation much better than what can be achieved with photon irradiation. The infiltrative nature of IDH-mutated grade II and III diffuse glioma, however, renders proton therapy a potential problem. A randomized controlled trial (RCT) is the only option when trying to ensure that chances of long-term survival are not impaired seeking to reduce unwanted late treatment effects. Non-inferiority of proton therapy compared to photon irradiation is the primary endpoint of the RCT. Hence, PRO-GLIO has two main objectives. First, PRO-GLIO will evaluate if proton therapy is safe in patients with IDH-mutated grade II and III diffuse glioma, showing that survival figures at 2 years from radiotherapy are not poorer in the proton arm than in the photon arm. Second, we want to find the true number of patients in need of rehabilitation in both arms, and evaluate if proton therapy conveys a higher QoL than photon irradiation at 2 years from radiotherapy.