Previous evidence has indicated that resection for recurrent glioblastoma might benefit the prognosis of these patients in terms of overall survival. However, the demonstrated safety profile of this approach is contradictory in the literature and the specific benefits in distinct clinical and molecular patient subgroups remains ill-defined. The aim of this study, therefore, is to compare the effects of resection and best oncological treatment for recurrent glioblastoma as a whole and in clinically important subgroups.

This study is an international, multicenter, prospective observational cohort study. Recurrent glioblastoma patients will undergo tumor resection or best oncological treatment at a 1:1 ratio as decided by the tumor board. Primary endpoints are: 1) proportion of patients with NIHSS (National Institute of Health Stroke Scale) deterioration at 6 weeks after surgery and 2) overall survival. Secondary endpoints are: 1) progression-free survival (PFS), 2) NIHSS deterioration at 3 months and 6 months after surgery, 3) health-related quality of life (HRQoL) at 6 weeks, 3 months, and 6 months after surgery, and 4) frequency and severity of Serious Adverse Events (SAEs) in each arm. Estimated total duration of the study is 5 years. Patient inclusion is 4 years, follow-up is 1 year.

The study has been approved by the Medical Ethics Committee (METC Zuid-West Holland/Erasmus Medical Center; MEC-2020-0812). The results will be published in peer-reviewed academic journals and disseminated to patient organisations and media.

This is an international, multicenter, prospective, cohort study. Eligible patients are operated or receive best oncological treatment with a 1:1 ratio with a sequential computer-generated random number as subject ID. Intraoperative mapping techniques and/or surgical adjuncts can be used in both treatment arms to ensure the safety of the resection (to minimize the risk of postoperative deficits).

Study patients undergo tumor re-resection or receive best oncological treatment and will undergo evaluation at presentation (baseline) and during the follow-up period at 6 weeks, 3 months, and 6 months postoperatively. Motor function will be evaluated using the NIHSS (National Institute of Health Stroke Scale) and MRC (Medical Research Council) scale. Language function will be evaluated using a standard neurolinguistic test-battery consisting of the Aphasia Bedside Check (ABC), Shortened Token test, Verbal fluency, Picture description and Object naming. This neurolinguistic test-battery is the result of a consensus between the participating centers. Cognitive function will be assessed using the Montreal Cognitive Assessment (MOCA). Overall patient functioning with be assessed with the Karnofsky Performance Scale (KPS) and the ASA (American Society of Anesthesiologists) physical status classification system for comorbidities. Health-related quality of life (HRQoL) will be assessed with the EQ-5D questionnaire and the EORTC QLQ-C30 and EORTC QLQ-BN20 questionnaires. Overall survival and progression-free survival will be assessed. We expect to complete patient inclusion in 4 years. The estimated duration of the study, including follow-up, will be 5 years.

The primary study objective is to evaluate the safety and efficacy of re-resection versus best oncological treatment (neurological morbidity and overall survival) in recurrent glioblastoma patients as expressed by NIHSS scores and survival data. Secondary study objectives are to study the overall progressive-free survival (PFS), long-term neurological morbidity (3 months and 6 months postoperatively), health-related quality of life (HRQoL), and Serious Adverse Events (SAEs) after resection versus best oncological treatment as expressed by progression on follow up MRI scans based on the RANO criteria24 for tumor progression; NIHSS scores, quality of life questionnaires (EORTC QLQ C30, EORTC QLQ BN20, EQ-5D), and registration of SAEs.

Patients will be recruited for the study from the neurosurgical or neurological outpatient clinic or through referral from general hospitals of the participating neurosurgical hospitals of the ENCRAM Research Consortium, located in Europe and the United States.

Inclusion Criteria:

1. Age ≥18 years and ≤90 years
2. Tumor recurrence according to the RANO criteria of a previously diagnosed glioblastoma based on the WHO 2021 classification for glioma
3. The tumor is suitable for resection (according to neurosurgeon)
4. Written informed consent

Exclusion Criteria:

1. Tumors of the cerebellum, brainstem, or midline
2. Medical reasons precluding MRI (e.g., pacemaker)
3. Inability to give written informed consent
4. Secondary high-grade glioma due to malignant transformation from low-grade glioma
5. Clinical data unavailable for the newly diagnosed setting

Patients with recurrent glioblastoma will be recruited from the neurosurgical or neurological outpatient clinic or through referral from general hospitals of the participating neurosurgical hospitals, located in Europe and the United States. The study is carried out by centers from the ENCRAM Consortium.