Berry 1979

Methods	RCT with allocation concealment and randomisation through central sealed envelope allocation. Patient, outcome assessors and treating team all aware of allocation at the start of treatment. No indication of power calculation
Participants	24 adults with SCC of the head and neck where radiotherapy was the treatment of choice. 11 allocated to HBOT and 13 to control. No dropouts, but two participants crossed from HBOT to control after refusing HBOT
Interventions	Control: between 4450 and 5500 rads in 15 or 20 fractions over 3 weeks HBOT: 400 to 4500 rads in 10 fractions over 3 weeks, pressure and time not specified but likely to have been 3 ATA for 30 to 40 minutes total exposure time
Outcomes	Death at 1 and 5 years, local recurrence at 5 years
Notes	Also see Berry 1968
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk
Allocation concealment (selection bias)	Low risk