Andersen 1978.

Study characteristics
Methods	Randomised, phase III trial Treatment period: 1963–1967 Follow‐up: 3 years
Participants	108 adults with glioblastoma (grade IV astrocytoma) from 4 US medical centres; 73% aged 50–70 years; baseline performance status not described; 64% men and 36% women
Interventions	Arm 1: postoperative radiotherapy: 4500 cGy in daily fractionation over 4.5–5.0 weeks Arm 2: no postoperative radiotherapy
Outcomes	Crude survival presented as survival curves up to 20 months
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Participants born on odd dates received postoperative radiotherapy whereas those born on even dates did not.
Allocation concealment (selection bias)	High risk	Randomisation was based on odd or even dates of birth. The protection of treatment allocation before and until assignment was deemed to be at high risk of bias.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding of participants and personnel was not possible due to the nature of radiation delivery. However, blinding would not have biased the outcome of survival.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Although there was no blinding of the outcome (survival), blinding would not have biased the assessment of this outcome.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition not described.
Selective reporting (reporting bias)	Low risk	The study's prespecified outcome (survival) that was of interest in this review was reported in the prespecified way.
Other bias	Unclear risk	Size of study bias: 108 participants.