Imaging timing after glioblastoma surgery (INTERVAL-GB): protocol for a UK and Ireland, multicentre retrospective cohort study Link to paper in BMJ Open Authors Gillespie CS, Bligh ER, Poon MTC, Solomou G, Islim AI, Mustafa MA, Rominiyi O, Williams ST, Kalra N, Mathew RK, Booth TC, Thompson G, Brennan PM, Jenkinson MD, INTERVAL-GB Collaborative, British Neurosurgical Trainee Research Collaborative (BNTRC) Abstract Introduction Glioblastoma is the most common malignant primary brain tumour with a median overall survival of 12–15 months (range 6–17 months), even with maximal treatment involving debulking neurosurgery and adjuvant concomitant chemoradiotherapy. The use of postoperative imaging to detect progression is of high importance to clinicians and patients, but currently, the optimal follow-up schedule is yet to be defined. It is also unclear how adhering to National Institute for Health and Care Excellence (NICE) guidelines—which are based on general consensus rather than evidence—affects patient outcomes such as progression-free and overall survival. The primary aim of this study is to assess MRI monitoring practice after surgery for glioblastoma, and to evaluate its association with patient outcomes. Methods and analysis ImagiNg Timing aftER surgery for glioblastoma: an eVALuation (INTERVAL) of practice in Great Britain and Ireland is a retrospective multicentre study that will include 450 patients with an operated glioblastoma, treated with any adjuvant therapy regimen in the UK and Ireland. Adult patients ≥18 years diagnosed with glioblastoma and undergoing surgery between 1 August 2018 and 1 February 2019 will be included. Clinical and radiological scanning data will be collected until the date of death or date of last known follow-up. Anonymised data will be uploaded to an online Castor database. Adherence to NICE guidelines and the effect of being concordant with NICE guidelines will be identified using descriptive statistics and Kaplan-Meier survival analysis. Ethics and dissemination Each participating centre is required to gain local institutional approval for data collection and sharing. Formal ethical approval is not required since this is a service evaluation. Results of the study will be reported through peer-reviewed presentations and articles, and will be disseminated to participating centres, patients and the public. Keywords Brain imaging Glioblastoma Neurosurgery Radiotherapy Citation Gillespie CS, Bligh ER, Poon MTC Neurology and Neurosurgery Interest Group (NANSIG), et al. Imaging timing after glioblastoma surgery (INTERVAL-GB): protocol for a UK and Ireland, multicentre retrospective cohort study. BMJ Open 2022;12:e063043. doi: 10.1136/bmjopen-2022-063043 Related links Link to paper in BMJ Open Dr Gerry Thompson Dr Paul Brennan Dr Michael Poon Brain & nervous system Glioblastoma Social media tags and titles Featured paper: Imaging timing after glioblastoma surgery (INTERVAL-GB): protocol for a UK and Ireland, multicentre retrospective cohort study @EdinUniBrainSci Publication date 25 Oct, 2022