CONVENTIONAL RADIOTHERAPY COMBINED WITH CARBOGEN BREATHING AND NICOTINAMIDE FOR MALIGNANT GLIOMAS

High grade malignant gliomas are among the most radioresistant human t umors and total doses up to 80 Gy are inadequate to achieve long-term local control in most of the patients. Hypoxia has been demonstrated i n primary brain tumors and may be one of the reasons for their radiore sistance. In experimental models carbogen breathing and nicotinamide h ave been shown to act against hypoxia by different mechanisms and both modalities were tested in 16 patients with supratentorial malignant g liomas in combination with a conventional radiotherapy scheme (50 Gy i n 25 daily fractions), The present study was performed to determine th e feasibility and toxicity of conventional radiotherapy combined with carbogen breathing and nicotinamide. The unexpectedly high incidence o f acute liver toxicity, the possible increase of subacute and late CNS toxicity, and the absence of a higher effectivity led us to reconside r this new treatment modality for patients with malignant gliomas.