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Hyperbaric Oxygen Therapy for Radionecrosis: Clear Advice From Confusing Data

Hull and East Riding Hospital, Analaby, East Yorkshire, UK

To the Editor:

The study by Annane et al¹ violated an ethical principle by exposing the control group to the potentially serious risk of acute decompression illness; a risk not present in the treatment group.² The trial involved the control group breathing a gas mixture of 9% oxygen and 91% nitrogen at treatment pressure (the placebo) to simulate breathing air at atmospheric pressure. This procedure requires mandatory decompression (controlled return to atmospheric pressure) to de-nitrogen the patients. This decompression was not a requirement for the oxygen-breathing (treatment) group. Decompression dives are not advised by some sports scuba diving organizations.³ Additionally, Annane et al, are mistaken in stating "a similar placebo has recently been used to evaluate HBO [hyperbaric oxygen therapy]." In the trial, they found that the control arm breathed a mixture of 60% nitrogen, 40% oxygen, negating the risk of decompression illness.⁴

Another issue requiring clarification is the number of patients who actually completed their prescribed treatment sessions. For example, the data show that at least 75% of the treatment group failed to receive the protocol minimum of 30 treatments. Furthermore, 26 of patients (48.1%) in stage A mandibular osteoradionecrosis at enrolment progressed to stage B, thus requiring them to complete a total of 40 sessions. No clear information is given about the compliance of these patients. Their Table 2 also indicated that very few sessions were stopped due to complications. Thus the question arises, why did at least 75% of patients not complete 30 treatments and what of the subgroup requiring 40? Additionally, it is unclear how in Table 2 there can be two patients with two sessions "discontinued due to complications," but only one patient with two sessions in which complication arose.

Other anomalies detract the reader from accepting the trial design and execution. For example, as with development, the evolution of osteoradionecrosis is variable.⁵ How was this variable accounted for in the small numbers involved in the triangular test? It would also be of interest to know how many of the 12 participating centers used hyperbaric oxygen before the trial and how many (if any) have continued with its use. As the accompanying editorial points out, this study is "under-powered." Therefore, to conclude with an unequivocal statement based on a trial involving literally only a handful of compliant patients is surprising. This study does, however, highlight that further research is urgently needed before giving any definitive advice about treating this painful and debilitating condition.

Author's Disclosures of Potential Conflicts of Interest

The author or his immediate family members have indicated a financial interest. No conflict exists for drugs or devices used in a study if they are not being evaluated as part of the investigation. Employment: Gerard Laden, North of England Medical and Hyperbaric Servcies Ltd. For a detailed description of these categories, or for more information about ASCO's conflict of interest policy, please refer to the Author Disclosure Declaration and the Disclosures of Potential Conflicts of Interest section of Information for Contributors found in the front of every issue.

REFERENCES

1. Annane D, Depondt J, Aubert P, et al: Hyperbaric oxygen therapy for radionecrosis of the jaw: A randomized, placebo-controlled, double-blind trial from the ORN96 study group. J Clin Oncol 22:4893-4900, 2004[Abstract/Free Full Text]

2. Helsinki Declaration: World Medical Association. 52nd General Assembly 2002, Edinburgh, Scotland, October 2002

3. Professional Association of Diving Instructors. http://www.padi.com

4. Pritchard J, Anand P, Broome J, et al: Double-blind randomized phase II study of hyperbaric oxygen in patients with radiation-induced brachial plexopathy. Radiother Oncol 58:279-286, 2001[CrossRef][Medline]

5. Turner SL, Slevin NJ, Gupta NK, et al: Radical external beam radiotherapy for 333 squamous carcinomas of the oral cavity–evaluation of late morbidity and a watch policy for the clinically negative neck. Radiother Oncol 41:21-29, 1996[Medline]

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This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Laden, G. Search for Related Content PubMed PubMed Citation Articles by Laden, G. Social Bookmarking                            What's this?