Abstract
The overall age-adjusted incidence rate of brain tumors in Japan was reported to be 14.1 (11.6 for males, 16.4 for females) per 100,000 population per year and it is almost the same as that in the United States (19.3 per 100,000). The most common tumors in both Japan and the USA are meningiomas, gliomas, pituitary adenomas, neurinomas and primary CNS lymphomas. Gliomas are the most common malignant brain tumors and the new incidence of gliomas are supposed to be about 4,000-5,000 patients per year. Gliomas are rare cancers and the prognoses of grade 2/3 gliomas have improved for 40 years, however, the prognosis of glioblastoma has remained poor and a 5-year overall survival rate is still under 10% and as such it is the worst prognostic cancer. The standard therapy for grade 2 gliomas is maximal resection + single radiation therapy (RT) and for grade 3/4 malignant gliomas it is maximal resection+RT+temozolomide (TMZ), but these protocols are still controversial. One of the reasons that gliomas continue to have poor prognoses is that there are few chemotherapeutic agents against them. Neurosurgeons and neuro-oncologists have to know the evidence of the treatments for gliomas and we have to attend many clinical trials around the world in order to improve the prognoses of malignant gliomas.
