ABSTRACT
BACKGROUND: Hyperbaric oxygen (HBO) therapy is the inhalation of 100% oxygen at a pressure of at least 1.5 atmospheres absolute (150 kPa). It uses oxygen as a drug by dissolving it in the plasma and delivering it to the tissues independent of hemoglobin. For a variety of organ systems, HBO is known to promote new vessel growth into areas with reduced oxygen tension due to poor vascularity, and therewith promotes wound healing and recovery of radiation-injured tissue. Furthermore, tumors may be sensitized to irradiation by raising intratumoral oxygen tensions. METHOD: A network of hyperbaric facilities exists in Europe, and a number of clinical studies are ongoing. The intergovernmental framework COST B14 action "Hyperbaric Oxygen Therapy" started in 1999. The main goal of the Working Group Oncology is preparation and actual implementation of prospective study protocols in the field of HBO and radiation oncology in Europe. RESULTS: In this paper a short overview on HBO is given and the following randomized clinical studies are presented: a) reirradiation of recurrent squamous cell carcinoma of the head and neck after HBO sensitization; b) role of HBO in enhancing radiosensitivity on glioblastoma multiforme; c) osseointegration in irradiated patients; adjunctive HBO to prevent implant failures; d) the role of HBO in the treatment of late irradiation sequelae in the pelvic region. The two radiosensitization protocols (a, b) allow a time interval between HBO and subsequent irradiation of 10-20 min. CONCLUSION: Recruitment of centers and patients is being strongly encouraged, detailed information is given on www.oxynet.org.
Subject(s)
Hyperbaric Oxygenation/methods , Neoplasms/therapy , Radiotherapy/methods , Combined Modality Therapy/methods , Humans , Randomized Controlled Trials as Topic , Treatment OutcomeABSTRACT
Normal tissue injury may lead to severe, life threatening, late side effects after therapeutic use of irradiation. Neurological complications caused by radiation of the spinal cord are ascribed to progressive, irreversible damage to the vasculature. Hyperbaric oxygen (HBO) is known to induce angiogenesis in irradiated tissue and has been proven to reduce late radiation injury in several normal tissues when applied during the latent period before complications become manifest. In the present study: (1). the prophylactic potential of HBO; (2). optimal timing of HBO therapy after spinal cord irradiation, i.e. during the latent period; and (3). effect of HBO on the re-irradiation tolerance of the spinal cord were investigated. The rat cervical spinal cord was locally X-ray irradiated with ten fractions of 6.5 Gy in 11 days. Five treatment groups (n=10) included: irradiation alone and irradiation followed by 30 HBO treatments (100% oxygen at 240 kPa for 90 min) during latency, with HBO starting either immediately, 5, 10 or 15 weeks after the primary irradiation course. One year after the primary treatment, the same spinal cord volume was re-irradiated with 20 Gy single dose. During life span, the animals were observed on the incidence of myelitis and the duration of the latent period. The actuarial analysis revealed no significant difference in neurological complications free survival between the irradiation alone and the irradiation+HBO treatment groups. A tendency towards radiosensitization was found in the group in which the primary irradiation course was immediately followed by the HBO treatment course. The data show that HBO applied during the latent period of progressively developing irradiation damage to the spinal cord does not increase the re-irradiation tolerance of this tissue.
