Dosimetric predictors of toxicity in a randomized study of short-course vs conventional radiotherapy for glioblastoma

•Critical structure constraints used in our randomized controlled trial of short-course versus conventional radiotherapy for patients with glioblastoma were appropriate for limiting grade 2 or higher toxicities.•Higher left-hippocampal mean doses were the most predictive for neuro-cognitive decline post-radiotherapy.•Routine contouring and use of dose constraints for the hippocampus is recommended.•Our left hippocampus sparing treatment model may help minimize neuro-cognitive decline in patients with glioblastoma treated with radiotherapy.