INDIGO – individualized, model-guided optimization of proton beam treatment planning in patients with low grade glioma

• Applicant: Privatdozent Semi Harrabi, Ph.D.
• Subject Area: Nuclear Medicine, Radiotherapy, Radiobiology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 508784421

Patients treated with radiotherapy for low grade glioma usually have a good prognosis. Since patients with low grade glioma are expected to become long-term survivors the prevention of long-term sequelae is particularly important. Not only disease progression but also treatment related side effects such as decline of neurocognitive function, endocrine impairment or sensorineural deficits can have a negative impact on patient’s quality of life. Owing the biophysical properties of protons with an inverse depth dose profile compared to photons and a steep dose fall of to the normal tissue there is a strong rationale for the use of proton beam therapy in the treatment of patients with low-grade glioma. While there is growing evidence for reduced toxicity of intracranial radiotherapy by the use of protons such as decreased cognitive ability, endocrine impairment or loss of sensorineural function the identification and understanding of other treatment associated and potentially proton beam therapy specific side effects must be prioritized. More particularly, there is a growing number of reports dealing with an apparently increased incidence of imaging changes or clinically relevant radiation induced brain injury. These lesions do not occur at random sites, but are highly concentrated to regions, where beam parts of increased biological effectiveness coincide with the fringe around the brain ventricles. Most of these imaging changes do not cause severe symptoms, however, there is a risk that they may delevop into brain necrosis. These clinical observations provide a strong rationale to support the hypothesis that the relative biological effectiveness of protons is variable and different to the fixed factor of 1.1 currently used worldwide. The underestimation of applied dose in some parts of the beam emphasize the need for biologically optimized treatment planning. The aim of this trial is to minimize the risk for radiation induced brain injuries using a novel, individualized model-guided optimization for treatment planning.

• DFG Programme: Clinical Trials
• Co-Investigators: Professor Dr. Jürgen Debus; Professorin Dr. Mechthild Krause; Dr. Johannes Krisam