| Research Abstract |
Low dose rate radiation therapy has many biological advantages, that is, it decreases oxygen enhancement ratio, reoxygenation is effectively occurred during the treatment, and there are a lot of chance that tumor cells of sensitive phase are attacked by it. We already tried this low-dose-rate therapy for 182 inoperable cancer cases using tele-cobalt machines. As a result of the research, we got the following conclusions, Idea control rate was unexpectedly high and late complication rate was also high. High incidence of late complication is probably developed from the radiation technique, because we. used old type tele-cobalt unit. In this study, we intended do try low-dose-rate teletherapy using 3D treatment method by Liniac. However, it's reported that superfractionation by 0.5 Gy/fraction is as effective as low-dose-rate therapy for hypoxic cancer cells, and patients are more torelable for superfractionation by Liniac 3D treatment. Twenty one patients with inoperable advanced cancer were treated with 60 Gy by conventional fractionatioh followed by 10 Gy of superfractionation : 0.5 Gy/fractionation, and 4 times/day. There was no acute complication. One esophageal cancer developed esophago-mediastinal fistula. Fifteen fresh esophageal cases (SHF) were compared with 83 esophageal cancers treated with low-dose rate teletherapy (LDRT). CR cases were 10(67%) in SHF group/and 28(34%) in LDRT group. Survival rates of 18 month were 70% in SHF group and 20% in LDRT group, and those of Stage IIA cases were 74% in SHF group and 27% in LDRT group. Although follow-up period of SHF group is short, the treatment results of SHF group are relatively better. This method also occupies one Liniac machine, and we need the further trial by the aid of multi-center.
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