van den Bent 2006.

Study characteristics
Methods	Randomized controlled trial
Participants	368 AO or AOA 3 of 5 anaplastic features
Interventions	Surgery + RT + PCV vs. surgery + RT
Outcomes	Overall survival Progression‐free survival Toxicity Quality of life
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: ''... patients were randomly assigned.'' Comment: probably done.
Allocation concealment (selection bias)	Low risk	Quote: ''Patients were stratified by age (< 40 v ≥ 40 years), extent of resection (biopsy v resection), WHO ECOG PS (0 or 1 v 2), and possible prior surgery for low‐grade oligodendroglioma (yes v no). Treatment was assigned using the minimization technique of Simon and Pocock to ensure balance with respect to the stratification factors.'' Comment: probably done.
Blinding (performance bias and detection bias) All outcomes	High risk	Not blinded.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No mention of loss to follow‐up.
Selective reporting (reporting bias)	Low risk	Outcomes reported adequately.

AA: anaplastic astrocytoma; AO: anaplastic oligodendroglioma; AOA: anaplastic oligoastrocytoma; ECOG: Eastern Cooperative Oncology Group; KPS: Karnofsky Performance Scale; PCV: procarbazine, lomustine and vincristine; PS: performance status; RT: radiotherapy; WHO: World Health Organization.