The
addition of hyperbaric oxygen during irradiation of carcinomas of the head and
neck and urinary bladder did not result in statistically significant improvement
in survival at six months.
Clinical Bottom Line:
1.
A trend to improved survival at six months with tumours of the head and neck
treated with hyperbaric oxygen while being irradiated.
2.
Improved survival at four months with tumours of the urinary bladder treated
with hyperbaric oxygen during irradiation.
Appraised
by: Mike Bennett, Dept. of Diving and
Hyperbaric Medicine, Prince of Wales Hospital
Sydney; Monday, 29 March 1999
Clinical
Scenario:
A patient with a squamous cell tumour of the tonsillar fossa presented
for radiotherapy.
Three-part
Question: For patients with tumours of
either the head and neck or bladder, does the addition of hyperbaric oxygen to
the usual radiotherapy regimen result in any improvement in survival?
Search
Terms: Carcinoma/ head and neck,
bladder
The
Study:
Non-blinded pseudo-randomised
controlled trial without intention-to-treat.
Patients with carcinoma of the
head and neck or bladder, without metastases and with prognosis sufficient to
expect survival for long enough to assess tumour response.
Control
group 1. Head and neck. (N = 12; 11
analysed): A 4 dose fractionation regimen of 775 rads/dose as an outpatient.
2. Bladder. (N = 8; 8 analysed):
A 6 dose fractionation regimen of 550 rads/fraction as an outpatient.
Experimental
group 1. Head and neck. (N = 17; 15
analysed): A 4 dose schedule as above but with a dose of 725 rads/fraction while
breathing 100% oxygen at 4ATA for a total chamber time of 44 minutes. Patients
largely treated in hospital.
2. Bladder. (N = 8; 8 analysed):
A 6 fraction dose schedule as above but with a dose of 500 rads/fraction while
breathing oxygen as for group one.
The
Evidence:Head and Neck
|
Outcome |
Time
to Outcome |
Air
group |
HBO
group |
Relative
risk reduction |
Absolute
risk reduction |
NNT |
|
Persistent
tumour |
6
months |
0.833 |
0.471 |
43% |
0.36 |
3 |
|
95%
CI: |
|
|
|
5%
to 82% |
0.04
to 0.68 |
1
to 22 |
|
Death |
6
months |
0.36 |
0.2 |
44% |
0.16 |
-6 |
|
95%
CI: |
|
|
|
-48%
to 100% |
-0.17
to 0.49 |
NNT=5
to INF NNH=2 to
INF |
Bladder
|
Outcome |
Time
to Outcome |
Air
group |
HBO
group |
Relative
risk reduction |
Absolute
risk reduction |
NNT |
|
Death |
4
months |
0.62 |
0.12 |
81% |
0.5 |
2 |
|
95%
CI: |
|
|
|
30%
to 100% |
0.19
to 0.82 |
2
to 6 |
Comments:
1. Small studies with presumed
low power to detect a clinically useful improvement in the survival rate.
2. Short term figures only given
and bladder tumour survival is preliminary data only.
3. Higher dose hyperbaric oxygen
and lower number of fractions of radiotherapy than most later studies.
4. Relevance to treatment today
is limited.
Expiry date: January 2004
References:
