Haffty
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 | NNT3 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 | NNT36 to INF NNH2 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: July 2020 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.
