Hyperbaric oxygenation and a smaller number of fractions for irradiation was not associated with improved survival or local recurrence rate in carcinoma of the cervix.

Clinical Bottom Line:
1. No evidence of a benefit with smaller number of fractions and hyperbaric oxygen with regard to survival or local recurrence rates.
2. A trend to improved local control rate in those actually receiving hyperbaric oxygen was not statistically significant.
3. There was also a trend in the oxygen group to a greater risk of treatment complications.
Appraised by: Mike Bennett, Dept of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney; Friday, 19 February 1999

Clinical Scenario: A patient with carcinoma of the cervix presented for radiotherapy. We wondered if irradiation while having hyperbaric oxygen would result in improved tumour control or survival.
Three-part Question: In patients with carcinoma of the cervix who present for radiotherapy, does the conduct of radiotherapy while in hyperbaric oxygen, compared to irradiation in air, result in any improvement in local or distant tumour control, or survival?
Search Terms: Hyperbaric oxygenation, tumour/cervix

The Study:
Non-blinded randomised controlled trial without intention-to-treat. Patients with stage IIB to IVA cervical cancer presenting for radiotherapy at one of four treatment centres.
Control group (N = 29; 29 analysed): 5,000 rads total dose over 5 weeks with 25 fractions (1,530 rets) in air. Intracavitary irradiation where possible.
Experimental group (N = 29; 29 analysed): 4,000 rads over 5 weeks with 10 fractions (1,524 rets) in oxygen at 3ATA for up to 45 minutes. Intracavitary irradiation where possible.

The Evidence:

Outcome
Time to Outcome
Air group
HBO group
Relative risk increase
Absolute risk increase
NNH
Death
4 years
0.59
0.62
5%
0.03
33
95% CI:



-38% to 48%
-0.22 to 0.28
NNH=4 to INF NNT=5 to INF
Local recurrence
4 years
0.276
0.345
25%
0.07
-14
95% CI:



61% to 100%
-0.17 to 0.31
NNH=3 to INF NNT=6 to INF
Treatment complications and no tumour
4 years
0.069
0.172
149%
0.10
-10
95% CI:



-91% to ?%
-0.06 to 0.27
NNH=4 to INF NNT=16 to INF

Comments:
1. Small trial in which 10/29 patients randomised to hyperbaric oxygen did not receive it.
2. Trends to lower rate of local recurrence and higher rate of treatment complications in the hyperbaric oxygen group when not analysed by intention to treat.

Expiry date: January 2004
References: 1.Brady LW, Plenk HP, Hanley JA, Glassburn JR, Kramer S, Parker RG. Hyperbaric oxygen therapy for carcinoma of the cervix- stages IIB, IIIA, IIIB and IVA: results of a randomised study by the radiation therapy oncology group. International Journal of Radiation Oncology, Biology and Physics 1981;7:991-998.


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