Glassburn 1974

Methods	RCT with allocation concealment not clear, method of randomisation not stated. Patient, outcome assessors and treating team all aware of allocation. No indication of power calculation. Participants excluded if second primary, prior radiotherapy or contraindication to HBOT
Participants	40 adults with Stage III or IV carcinoma of the uterine cervix where radiotherapy was the treatment of choice. 17 allocated to HBOT and 23 to control. No dropouts or losses to follow‐up
Interventions	Control: 6000 external beam in 24 fractions over six weeks plus radium implant HBOT: same regimen, but dose reduced by 7% after first six participants displayed high rate of gastrointestinal complications. All external beam radiotherapy conducted at 3 ATA breathing 100% oxygen, total compression time about 40 minutes
Outcomes	Death at 27 months, local tumour recurrence at 27 months, metastases at 27 months
Notes	An interim report that does not seem to have been reported in a complete paper to date. Also see Faust 1969 Schulz rating: randomisation: C; allocation concealment: B; selection bias: A; blinding: C
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear