An Application of Holmium-166-Chitosan Complex to an Oral Cancer Therapy

摘要

Radiation therapy has been used for the oral cancer treatment as a main treatment modality. The purpose of this study was to evaluate the possibility the Ho-166-chitosan complex for oral cancer therapy. The KB cell line was injected into the flank of the athymic mice to induce the human oral cancer. In this animal model, it was measured the organ leakages of the radioisotope and the tumor size after intratumoral injection. The major organs of the mice injected with the Ho-166-chitosan complex showed much lower radioactivity than those of the mice with the Ho-166 alone. The sum of the radioactivity in major organs at 24 hours after the intratumoral administration was 0.6 ± 0.01 %ID/g(x10~()-4) for the Ho-166-chitosan and 6,966 ± 1,020 %ID/g(x10~()-4) for the Ho-166 alone. The tumor size was decreased until three weeks in the Ho-166-chitosan complex injected group whereas the tumor grew up in the control group. The tumor volume of Ho-166-chitosan group was 7.4 times smaller than that of the control group. The above data suggests that most of the Ho-166-chitosan complex is retained in the injected site and the complex suppressed the tumor growth. Thus the complex represents a promising candidate for oral cancer therapy.