| Research Abstract |
As a result of previous low-dose rate telecobalt therapy against 161 inoperable cancers, we got the following conclusions, that is, local control rate was unexpectedly high and late complication rate was also high. This high incidence of late complication is probably developed from the radiation technique that we used old type telecobalt unit which permits only one fixed portal irradiation. In this study we improved another telecobalt unit by which multi portal irradiation was possible with a high accuracy. Using this apparatus, from 1994 to 1996 we treated 21 advanced cancers, 13 esophageal cancers, 4 pancreatic cancers, 2 epipharynjeal carcinomas, one lung cancer and one uterine cervical cancer. We compared these treatment results with the previous treatment results of 161 cancers (control group). Radiation method was fundamentally same between these two groups, that is, patients received a total irradiation dose of 50-60Gy by conventionally fractionated method, following a total dose of 10-20Gy by the low-dose rate teletherapy (1Gy/hour, 5-7Gy/day). General fatigue of patients immediately after the low-dose rate teletherapy was slight in this study group. Late severe complication rate was 15% (20/133) in control group and 5% (1/21) in this study group. One-year survival rate was 32% in control group and 41% in this study group.The fact that two advanced pancreatic cancers of this study group survived long term with a good QOL promises bright future to us. A trial of low-dose rate teletherapy using a linear accelerator should be carried out, bacause a telecobalt unit has essentially a bigger half-shadow and a lower accuracy.
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