Abstract
Background: Although intensity-modulated radiation therapy (IMRT) has been developed as an alternative to conventional radiotherapy, but reducing bone marrow damage is limited in the patients with multiple tumor lesions and large irradiation volume. Thus, novel technology is needed to mitigate further IMRT-induced bone marrow damage. Molecular hydrogen (H2) was recently reported as a preventive and therapeutic antioxidant that selectively scavenges hydroxyl radical (·OH) and peroxynitrite (ONOO-). This observational study aims to examine whether H2 gas treatment improves IMRT-induced bone marrow damage in cancer patients. Methods: The patients with end stage of cancer were received IMRT once per day for 1 to 4 weeks except Saturday and Sunday. After each course of IMRT, the patients of control group (n = 7) were housed in health care chamber (HCC, mild hyperbaric oxygen chamber) for 30 minutes, and the patients of H2 group (n = 16) were also housed in HCC and received 5% H2 gas for 30 minutes once per day. Radiation-induced bone marrow damage was evaluated by hematological examination of peripheral blood obtained before and after IMRT, and the data was expressed the ratio of after treatment to before treatment.Results: The total number of radiation courses and total exposure doses of radiation were similar between the control and H2 groups. IMRT with HCC therapy significantly reduced white blood cells (WBC) and platelets (PLT), but not red blood cells (RBC), hemoglobin (HGB) and hematocrit (HT). In contrast, H2 gas treatment significantly alleviates reducing effects of WBC and PLT (p=0.0011 and p=0.0275, respectively). Bone marrow damage index calculated by total exposure dose and WBC ratio also demonstrated the radioprotective effects of H2 gas (p=0.0231). Tumor responses to IMRT were similar between the two groups, and 4 of 7 (57%) patients in the control group and 7 of 16 (44%) patients in the H2 group achieved a complete response (CR) or partial response (PR). In addition, 3 of 16 (19%) patients in the H2 group achieved stable disease (SD).Conclusion: The results obtained demonstrated that H2 gas inhalation therapy alleviated IMRT-induced bone marrow damage without compromising the anti-tumor effects of IMRT. The present study suggests that this novel approach of H2 gas inhalation therapy may be applicable to IMRT-induced bone marrow damage in cancer patients.
Protective effects of hydrogen gas inhalation on radiation-induced bone marrow damage in cancer patients: a retrospective observational study
