Improved
local resolution of tumour, but no improvement in survival following irradiation
of head and neck tumours while breathing oxygen at 4 atmospheres.
Clinical
Bottom Line:
1.
There was no improvement in 5 year survival through the addition of hyperbaric
oxygen
2.
There was improved local tumour control in the hyperbaric group, but a
non-significant increase in severe complications of therapy.
Appraised
by:
Kirsteen Brown and Mike Bennett, Prince of Wales Hospital, Sydney; Monday, 17
July 2000
Clinical
Scenario: A
patient with locally invasive SCC of the tongue presented for radiotherapy. We
wondered if the addition of hyperbaric oxygen during irradiation would improve
survival.
Three-part
Question:
For adult patients with SCC of the head and neck and requiring radiotherapy,
does irradiation under hyperbaric oxygenation, compared to irradiation breathing
air at 1ATA, improve survival, local recurrence or alter the incidence or
severity of complications?
Search
Terms:
Hyperbaric oxygenation, radiotherapy, head and neck neoplasms
The
Study:
Non-blinded
concealed randomised controlled trial without intention-to-treat.
Adult
patients with locally advanced SCCs of the head and neck in whom radiotherapy
was indicated as the primary therapy. No previous surgery, radiotherapy or
chemotherapy and all patients were fit for general anaesthesia.
Control
group (N = 25; 25 analysed): DXRT in two fractions (21 days apart) to a total
dose of 25.3 Gy delivered while breathing normobaric air.
Experimental
group (N = 23; 23 analysed): DXRT in two fractions (21 days apart) to a total
dose of 23 Gy delivered while under general anaesthesia at 4ATA breathing 100%
oxygen. Total chamber time about 40 minutes.
The
Evidence:
|
Outcome |
Time to Outcome |
Air group |
HBO group |
Relative risk reduction |
Absolute risk reduction |
NNT |
|
5 year survival |
5
years |
0.23 |
0.12 |
48% |
0.11 |
9 |
|
95% Confidence Intervals: |
|
|
|
-44%
to 100% |
-0.10
to 0.32 |
NNT=3
to INF NNH=10
to INF |
|
Response rate |
|
0.52 |
0.913 |
-76% |
-0.39 |
-3 |
|
95% Confidence Intervals: |
|
|
|
-100%
to -32% |
-0.62
to -0.17 |
-6
to -2 |
|
Complications |
|
0.28 |
0.522 |
-86% |
-0.242 |
-4 |
|
95% Confidence Intervals: |
|
|
|
-100%
to 10% |
-0.51
to 0.03 |
NNT=36
to INF NNH=2 to INF |
Comments:
1.
Unusual irradiation regime no longer common clinical practice.
2.
Hyperbaric oxygen administration required intubation and ventilation to avoid
problems from acute CNS oxygen toxicity.
3.
There was a trend to poorer five year survival in the oxygen group
4.
The trial was stopped early because of perceived benefits from hyperbaric oxygen
Expiry date: January 2004
References:
1.
Haffty BG, Peters LJ. Radiation therapy with hyperbaric oxygen at 4 atmospheres
pressure in the management of squamous cell carcinoma of the head and neck:
results of a randomized clinical trial. The Cancer Journal from Scientific
American 1999; 5:341-347.
