Hyperbaric oxygen therapy for late radiation tissue injury

Background Cancer is a significant global health problem. Radiotherapy is a treatment for many cancers and about 50% of patients having radiotherapy with be long-term survivors. Some will experience late radiation tissue injury (LRTI) developing months or years later. Hyperbaric oxygen therapy (HBOT) has been suggested as a treatment for LRTI based upon the ability to improve the blood supply to these tissues. It is postulated that HBOT may result in both healing of tissues and the prevention of problems following surgery. Objectives To assess the benefits and harms of HBOT for treating or preventing LRTI. Search methods In March 2011 we updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, Issue 1), MEDLINE, EMBASE, DORCTIHM and reference lists of articles. Selection criteria Randomised controlled trials (RCTs) comparing the effect of HBOT versus no HBOT on LRTI prevention or healing. Data collection and analysis Three review authors independently evaluated the quality of the relevant trials using the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions and extracted the data from the included trials. Main results Eleven trials contributed to this review (669 participants). For pooled analyses, investigation of heterogeneity suggested important variability between trials but there was some evidence that HBOT is more likely to achieve mucosal coverage with osteoradionecrosis (ORN) (risk ratio (RR) 1.3; 95% confidence interval (CI) 1.1 to 1.6, P = 0.003, number needed to treat for an additional beneficial outcome (NNTB) 5). From single studies there was a significantly increased chance of improvement or cure following HBOT for radiation proctitis (RR 1.72; 95% CI 1.0 to 2.9, P = 0.04, NNTB 5), and following both surgical flaps (RR 8.7; 95% CI 2.7 to 27.5, P = 0.0002, NNTB = 4) and hemimandibulectomy (RR 1.4; 95% CI 1.1 to 1.8, P = 0.001, NNTB 5). There was also a significantly improved probability of healing irradiated tooth sockets following dental extraction (RR 1.4; 95% CI 1.1 to 1.7, P = 0.009, NNTB 4). There was no evidence of benefit in clinical outcomes with established radiation injury to neural tissue, and no data reported on the use of HBOT to treat other manifestations of LRTI. These trials did not report adverse effects. Authors' conclusions These small trials suggest that for people with LRTI affecting tissues of the head, neck, anus and rectum, HBOT is associated with improved outcome. HBOT also appears to reduce the chance of ORN following tooth extraction in an irradiated field. There was no such evidence of any important clinical effect on neurological tissues. The application of HBOT to selected patients and tissues may be justified. Further research is required to establish the optimum patient selection and timing of any therapy. An economic evaluation should be undertaken.