Table 1.

Summary of recorded study variables

Recorded variable	Description
Baseline clinical and radiological	Age; date of surgery; sex; WHO performance status; presence of preoperative seizure activity; preoperative neurological deficit.
Radiological	Location; laterality; main anatomical area.
Surgical and histopathological	Extent of resection (gross total resection, subtotal resection or biopsy).
Histopathology	IDH status; MGMT promoter status.
Adjuvant treatment	Adjuvant radiotherapy start date; end date; radiotherapy dose and fractions; number of adjuvant temozolomide cycles completed.
Other supportive treatment	Enrolment into a clinical trial; reoperation for tumour; second-line or third-line chemotherapy; fourth-line chemotherapy; reirradiation; Referral to palliative care.
Follow-up imaging	Date of first postoperative MRI and indication; date of subsequent scans; if scans were unscheduled or scheduled; scan outcomes.
Outcome measures	Disease progression; overall survival.

All definitions can be found in the main text, and online supplemental appendix A

IDH, isocitrate dehydrogenase; MGMT, O6-methylguanine-DNA methyltransferase.