REMIND Maintenance Radiotherapy for Newly Diagnosed Glioblastoma

Glioblastoma is an aggressive primary brain tumor with high rates of local recurrence despite standard treatment with surgical resection, concurrent temozolomide and radiotherapy, and adjuvant temozolomide. This study is designed to test whether an additional single fraction of maintenance radiotherapy can be delivered safely and feasibly after standard-of-care treatment. REMIND is a single-center investigator-initiated study enrolling adult patients with newly diagnosed glioblastoma. Eligible participants will be consented before starting standard-of-care concurrent temozolomide and radiotherapy. Following enrollment, participants will enter an observational lead-in phase while receiving their prescribed standard-of-care therapy off study. During this lead-in phase, study data collection will be limited to routine electronic medical record abstraction to confirm standard-of-care treatment administration and monitor basic clinical status. Active study participation begins approximately 2 weeks after standard-of-care treatment, when participants undergo simulation for maintenance radiotherapy. Approximately 4 weeks after temozolomide, participants will receive maintenance radiotherapy consisting of one 2 Gy fraction delivered using intensity-modulated radiotherapy directed at the post-operative cavity and areas where previous enhancing disease was identified after surgical resection. The primary objective is to test the safety and feasibility of delivering maintenance radiotherapy. Safety will be evaluated by monitoring toxicities and adverse events, including Grade 4 or 5 toxicities related to the experimental 2 Gy radiotherapy fraction. Feasibility will be evaluated based on treatment completion. The secondary objective is to descriptively compare the frequency of myeloid-derived suppressor cells in peripheral blood before and after maintenance radiotherapy. Participants will be followed for disease response per standard of care every 2 to 4 months until death or for up to 5 years from maintenance radiotherapy.