Plenk 1972

Methods	RCT using random number table, allocation concealment not clear. Patient, outcome assessors and treating team all aware of allocation. No indication of power calculation
Participants	40 adults with carcinoma of the urinary bladder. 19 allocated to HBOT and 21 to control. More than 50% loss to follow‐up at two years
Interventions	Control: 6000 rads in 24 to 30 fractions over six weeks HBOT: 4800 rads in 12 fractions over about four weeks at 3 ATA breathing oxygen for about 40 minutes
Outcomes	Death at one and two years, oxygen toxicity
Notes	Schulz rating: randomisation: A; allocation concealment: B; selection bias: C; blinding: C
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear