Radioimmunotherapy in Solid Tumors (PNRR-MCNT2-2023-12378239-Aim2)

This is a prospective multicenter pilot study. Functional and spectroscopic neuroradiological imaging will be adopted for treatment planning. Specialized software will be used to perform radiomic feature extraction and analysis of pre-trained neural networks from the advanced MRI (magnetic resonance imaging) and CT (computed tomography) used for simulation, to identify distribution patterns of aggressive and radioresistant disease areas, with higher probability of disease recurrence, and to intensify the dose on the areas identified as more aggressive, in order to counteract intrinsic radioresistance. The hypofractionated radiotherapy paradigm claims the benefit of reduced treatment times, improved quality of life, better access to specialized treatment centers and potentially improved tumor outcomes with greater disease control and less tumor repopulation. The rationale for neoadjuvant RT is based on the idea of counteracting the tumor's aggressive mechanisms with radiotherapy before the disease is surgically removed, in order to maximize the immunostimulatory potential of RT, and therefore reduce recurrences. Neoadjuvant treatment offers numerous advantages, first of all the ability to adjust the dose to the pathological volume identified by MRI and limit the volume of irradiated healthy brain tissue. Furthermore, the use of imaging derived from functional neuroradiological and spectroscopic techniques for treatment planning would allow us to increase the dose on the areas identified as more aggressive, in order act against intrinsic radioresistance. One of the major risks could be the possibility of developing radionecrosis, but this would not be a cause for concern in the neoadjuvant setting, as all irradiated tissue will then be surgically removed. Patients who agree to participate in the study and who would be candidates for radical surgical treatment, according to the evaluation of the Neurosurgery Department of our Institute, will be treated. These patients will receive neoadjuvant radiation treatment in 5 fractions delivering 30 Gy on PTV and 35-50 Gy on GTV, with a dose-escalation modality that involves increasing the dose to 35-40-42.5-45-47.5-50 Gy in groups of 5 consecutive patients, using standard chemotherapy (TMZ) after surgery.

Current diagnostic brain MRI allows a good definition of the initial disease and its most aggressive areas. Since relapses have always been found to occur in irradiated areas and recent studies have shown that reducing margins does not affect overall survival, smaller margins will be used from GTV to CTV and from CTV to PTV. Therefore, smaller volumes will be generated and treated with hypofractionation. Biological equivalent doses (BED) to the standard prescription will be delivered, with boost to a higher biological equivalent dose, in the most aggressive areas, in order to obtain better local control, maintaining an acceptable level of toxicity and therefore improve the evolution of the disease. CE marked devices (software) will be used according to the approved use, for the definition of the target (CT and MRI) and for the delivery of the treatment (linear accelerators) and the standard drug, which has the authorization for marketing, will be prescribed. Radiomic features related to local response and survival will be identified, to obtain a predictive model. At the same time, we will collect PMBC and patient serum in the biobank to identify presumed immunocorrelated of therapy efficacy and/or predictive biomarkers of response/toxicity to therapy. For comparative purposes, serum from healthy volunteers will also be collected, in numbers equivalent to patients and with sex and age characteristics comparable to the latter.

• Disease Free Survival [Time frame: From the date of radiotherapy end until the date of first documented clinical progression or date of death from any cause, whichever came first, assessed up to 36 months]]
• Cancer Specific Survival [Time frame: From the date of radiotherapy end until the date of first documented clinical progression or date of death from any cause, whichever came first, assessed up to 36 months]]
• Overall survival [Time frame: From the date of radiotherapy end until the date of death from any cause, assessed up to 36 months]
• Local Relapse Free Survival [Time frame: From the date of radiotherapy end until the date of local progression or date of death from any cause, whichever came first, assessed up to 36 months]
• Intracranial Relapse Free Survival [Time frame: From the date of radiotherapy end until the date of local progression or date of death from any cause, whichever came first, assessed up to 36 months]
• Extracranial Relapse Free Survival [Time frame: From the date of radiotherapy end until the date of local progression or date of death from any cause, whichever came first, assessed up to 36 months]
• Late toxicity [Time frame: From three months after the start of radiotherapy until the end of follow-up or death, assessed up to 36 months]
• Subacute Toxicity [Time frame: From one up to three months after the start of radiotherapy]
• Incidence of Treatment-Emergent Adverse Events as assessed with brain tumor specific quality of life questionnaires [Time frame: 36 months]
• Incidence of Treatment-Emergent Adverse Events as assessed with functional-social- emotional and general well being questionnaires [Time frame: 36 months]
• Incidence of Treatment-Emergent Adverse Events as assessed with mental status questionnaires [Time frame: 36 months]
• Periferic mononuclear blood cells (PMBC) subtypes predictive for disease progression and death [Time frame: Form the start of radiotherapy up to 6 months]