The CONCISE trial: Condensed Chemoradiotherapy Schedule for Glioblastoma

This study compares two standards of care for radiotherapy in combination with temozolomide (TMZ). Investigational Arm • Hypo fractionated radiotherapy, 55 Gy delivered in 20 daily fractions over 4 weeks (5 fractions per week). Comparative (Standard of Care) Arm: • Conventional fractionated radiotherapy, 60 Gy delivered in 30 daily fractions over 6 weeks (5 fractions per week). Participants in both treatment arms will receive standard-of-care temozolomide chemotherapy administered concurrently with radiotherapy and as adjuvant therapy. Concurrent Temozolomide • Initiation: Concurrent during radiotherapy • Dose: 75 mg/m² orally once daily • Schedule: 7 days per week, including weekends • Duration: Throughout the course of radiotherapy Adjuvant Temozolomide • Adjuvant temozolomide will be initiated approximately 4 weeks (± 1 week) after completion of concurrent radiotherapy and temozolomide in both the Investigational and Comparative arms. • Adjuvant temozolomide in both arms must commence no later than 6 weeks after completion of concurrent RT + TMZ. • Dose: 150–200 mg/m² orally, based on prior tolerance • Schedule: Days 1–5 of each 28-day cycle • Duration: 6 cycles Temozolomide is administered as an oral capsule taken for five consecutive days in each 28-day cycle at the dose previously tolerated by the patient. Treatment adherence will be monitored during four-weekly clinical assessments. The study will also involve a focus on patient and carer-reported outcomes as well as an embedded health-economic analysis.