Hyperbaric oxygenation did not improve symptoms of radiation injury to the pelvis compared to a sham treatment

1. No benefit in radiation-related problems with HBOT compared to sham treatment at one year

Citation/s:1.Glover M, Smerdon GR, Andreyev HJ, Benton BE, Bothma P, Firth O, Gothard L, Harrison J, Ignatescu M, Laden G, Martin S. Hyperbaric oxygen for patients with chronic bowel dysfunction after pelvic radiotherapy (HOT2): a randomised, double-blind, sham-controlled phase 3 trial. The Lancet Oncology. 2016 Feb 1;17(2):224-33.
Lead author's name and fax: John Yarnold

Three-part Clinical Question:For patients with radiation proctitis, does treatment with hyperbaric oxygen, compared to a sham treatment, result in any symptomatic improvement?
Search Terms: STRI; radiation; proctitis

The Study:Double-blinded concealed randomised controlled trial with intention-to-treat.
The Study Patients: Adults with gastrointestinal symptoms attributed to late radiation tissue injury for at least 12 months and continuing despite three months of optimum standard treatment. (Median 42 months)
Control group (N = 29; various analysed): 40 sessions at 1.3 ATA breathing air for 90 minutes once daily for five days each week.
Experimental group (N = 55; various analysed): As above but breathing 100% oxygen at 2.4 ATA

The Evidence:IBDQ = Inflammatory Bowel Disease Questionnaire



Time to Outcome

Sham group

HBOT group

Relative risk reduction

Absolute risk reduction


Improvement in rectal bleeding on IBDQ

12 months






95% CIs:

-53% to 30%

-0.36 to 0.20

NNT = 5 to INF; NNH = 3 to INF


Non-Event Outcomes

Time to outcome

Control group

Experimental group


Improvement in LENT SOMA scores (Median and IQR)

12 months

N= 26

1.5 (4 to 0)

N = 46

1 (2 to -1)


Improvement in bowel function score (from IBDQ)

12 months

N = 23

4 (-6 to 9)

N = 46

3.5 (-3 to 11)



1. Well-conducted RCT with reliable blinding, allocation concealment and randomisation procedures.
2. Differences in symptomatology at entry and loss/incomplete follow-up such that different individual outcomes included different numbers of patients.
3. Less improvement in LENT SOMA scores with HBO than recorded in previous studies. Patients in this study had changes of longer duration (median 42 months) than other studies and relatively mild symptomatology. Also, the assessments were subjective rather than objective.
4. Probably under-powered to find a clinically useful improvement - sample size calculated on a big difference between groups of ARR 70%. Even the staunchest proponents of hyperbaric oxygen therapy would find this an optimistic prediction.
5. The modified IBDQ was developed and validated for patients with ulcerative colitis and Crohn’s disease and maybe inappropriate to use here.

Appraised by: Mike Bennett; Thursday, 14 May 2020

Kill or Update By: May 2022