EXPERIMENTAL COMPARATIVE INVITRO STUDY OF TARGETED RADIOTHERAPY USING 125IUdR AND EXTERNAL BEAM RADIATION IN TREATMENT OF GLIOMA

Gliomas comprise about 50% of all primary central nervous system tumors that have defied treatment. Despite of improvement in treatment with surgery, radiotherapy and chemotherapy, the prognosis for these patients remains poor. Efforts to improve the treatment of malignant glioma have included Targeted Radiotherapy with [125I]-Iododeoxyuridine. 125IUdR, a thymidine analogue, is preferentially incorporated into the DNA of tumor cells, and the Auger electrons emitter [125I] is highly toxic to dividing cells. We have achieved comparative study of Targeted Radiotherapy and external beam therapy in treatment of glioma. Clonogenic assays formed basis of experiments to the human glioma cell line “A172” cultured as monolayers in the exponential and the plateau phase. In external beam radiation, the survival curves were exhibited a distinct shoulder, in comparison with, lack of shoulder (absence of repair) in Targeted Radiotherapy. In the treatment of cells in the plateau, the effectiveness of 125IUdR was attenuated by the presence of non-cycling cells. These finding suggest that Targeted Radiotherapy may be a useful method for treatment of glioma, in case we overcome non-cyling malignant cells.