Hyperbaric
oxygenation during radiotherapy for advanced carcinomas of the oropharynx did
not result in improved survival or local tumour control.
Clinical Bottom Line:
1.
There was no evidence of improved survival or tumour clearance with the
addition of hyperbaric oxygen, although there were trends in this direction.
Appraised
by: Mike Bennett, Dept. of Diving and
Hyperbaric Medicine, Prince of Wales Hospital
Sydney; Friday, 9 April 1999
Clinical
Scenario: A patient presented with an
advanced oropharyngeal carcinoma for radiotherapy. We wondered if there was any
purpose in using adjunctive hyperbaric oxygen.
Three-part
Question: In patients with advanced
oropharyngeal carcinoma having radiotherapy, does irradiation while breathing
hyperbaric oxygen, compared to irradiation in air, result in any improvement in
local control or survival?
Search
Terms: head and neck cancer
The
Study:
Non-blinded randomised
controlled trial with intention-to-treat.
Patients with carcinoma of the
head and neck greater than 4cm with limited extension to adjacent structures (T3
and T4).
Control group (N = 25; 25
analysed): Two controls. One group had radiotherapy in air on a conventional
fractionation scheme of 6,000 rads over 30 treatments in 6 weeks, while the
other had 4,200 rads over 7 treatments in 3.5 weeks.
Experimental group (N = 26; 26
analysed): Irradiation while breathing oxygen 100% at 3ATA on a scheme of 3,600
rads over 6 treatments in 3 weeks.
The
Evidence:
|
Outcome |
Time to
Outcome |
Air groups |
HBO group |
Relative
risk reduction |
Absolute
risk reduction |
NNT |
|
Death |
5 years |
0.76 |
0.62 |
18% |
0.14 |
7 |
|
95% CI: |
|
|
|
-15% to 51% |
-0.11 to 0.39 |
NNT=3 to INF
NNH=9 to INF |
|
Local area
not cleared |
6 months |
0.52 |
0.31 |
40% |
0.21 |
5 |
|
95% CI: |
|
|
|
-10% to 91% |
-0.05 to 0.47 |
NNT=2 to INF
NNH=18 to INF |
|
Lymph nodes
positive |
6 months |
0.72 |
0.62 |
14% |
-0.10 |
10 |
|
95% CI: |
|
|
|
-22% to 50% |
-0.16 to 0.36 |
NNT=3 to INF
NNH=6 to INF |
Comments:
1. No blinding and two control
groups make interpretation difficult. There was no trend to different outcomes
in the two control groups.
2. The trend to improved control
and survival was not statistically significant in this small trial.
3. The relevance for treatment
today is unclear.
Expiry date: January 2004
References:
