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

  • End date
    Dec 31, 2041
  • participants needed
  • sponsor
    Oslo University Hospital
Updated on 21 March 2022


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.


PRO-GLIO aims at establishing proton irradiation as standard radiotherapy for IDH-positive diffuse glioma grade II and III patients. First, PRO-GLIO will show that proton therapy is safe, despite the infiltrative nature of these tumors. Second, the HRQOL and neuropsychological investigating part of PRO-GLIO will show that patients irradiated with protons have a better outcome in this regard than those irradiated with photons. Inclusion criteria are a diagnosis of grade II or grade III IDH-mutated diffuse glioma, good performance status, indication for radiotherapy and age between 18 and 65 years.

Patients will be randomized to proton or photon radiotherapy and the study work will be divided in three work packages (WP).

  1. In WP1, survival data will be the main focus, but the estimation of QALY will also be an important part - concentrating on differences between the two study arms. If there is truly no difference between the proton and photon radiotherapy on the probability of FIFS after two years, then 224 randomized patients (112 in each treatment group) are required to be 80% certain that the upper limit of a two-sided 95% confidence interval will exclude a difference in favor of the photon radiotherapy of more than 15%. This assumes a 0.8 probability of FIFS in the control arm, and no drop-outs.
  2. In WP2, a battery of validated neuropsychological tests will be used to test the cognive abilities of the patients. All patients will be testes using an internet-based test (Cog-State) and 1/3 of patients will also have an in-depth neuropsychological evaluation. The two methods will be compared.
  3. In WP3, a battery of patient-reported outcome measures (PROMS) questionnaires will be used to establish which subjective challenges this patient group struggles the most with.

Condition Oligodendroglioma, Oligodendroglioma, Anaplastic, Diffuse Astrocytoma, IDH-Mutant
Treatment radiation therapy
Clinical Study IdentifierNCT05190172
SponsorOslo University Hospital
Last Modified on21 March 2022


Yes No Not Sure

Inclusion Criteria

Patients must be 18 to 65 years old at the day of consenting
IDH-mutated astrocytoma grade II or III, or oligodendroglioma grade II or III according to WHO 2016
Indication for radiotherapy
WHO/ECOG performance status 0-2
Available MRI not older than 2 months at study inclusion, preferably including volumetric FLAIR-imaging
No significant contrast enhancing tumor at the time of randomization
Ability and willingness to travel to The Skandion Clinic for proton therapy if randomized to the proton therapy arm
Women of child-bearing potential (WOCBP) must agree to use an effective method of contraception during radiotherapy, chemotherapy and 1 year after completion of chemotherapy. Pregnancy is not an ineligibility criterium if radiotherapy is indicated and cannot be postponed
Ability to understand the information about the study and included treatment and give a written informed consent
Signed informed consent

Exclusion Criteria

Prior treatment (except surgery) for diffuse glioma
Concomitant or previous malignancies. Exceptions are adequately treated basal cell carcinoma or squamous cell carcinoma of the skin, or in situ carcinoma of the cervix uteri with a follow-up time of at least 3 years, or other previous malignancy with a disease-free interval of at least 5 years
More than 2 months from randomization to start radiotherapy
Known CDKN2A/B homozygous deletion
Presence of any medical, psychological, familial, sociological, or geographical characteristic that might impair patient compliance for study protocol procedures including follow-up
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