Hyperbaric oxygen as a chemotherapy adjuvant in the treatment of osteosarcoma

Abstract. Although hyperbaric oxygen has been shown toenhance the efficacy of radiotherapy and chemotherapyfor the treatment of several malignant tumors, the impactof hyperbaric oxygen on osteosarcoma has not yet beendemonstrated. In this study, we investigated the efficacy ofhyperbaric oxygen alone and in combination with an anti cancer drug as an adjuvant to chemotherapy. In vitro, highlymetastatic murine osteosarcoma cell lines were exposed tohyperbaric oxygen and cell viability was examined. Hyper baric oxygen alone significantly suppressed cell proliferation,and hyperbaric oxygen plus carboplatin exhibited significantsynergism in suppression of cell proliferation. In vivo, C3Hmice were subcutaneously inoculated with osteosarcomacells and divided into four groups: control, hyperbaric oxygen,carboplatin, and carboplatin plus hyperbaric oxygen. After5 weeks, increase in both tumor volume and number oflung metastases was significantly suppressed in the hyper baric oxygen group. Concomitant hyperbaric oxygen clearlyenhanced the chemotherapeutic effects of carboplatin on bothtumor growth and lung metastasis in osteosarcoma-bearingmice. Moreover, mortality in the carboplatin plus hyperbaricoxygen group was significantly lower than in the other threegroups. These findings suggest that hyperbaric oxygen pluscarboplatin combination therapy could be an appropriatetherapeutic regimen for the treatment of patients with osteo sarcoma