Overview

Brain tumor is a general term for neoplasms (tumors) that form inside the skull. Brain tumors are divided into primary brain tumors, which arise from the tissues that make up the brain itself, and metastatic brain tumors, which are malignant tumors in other organs that have spread to the brain. Brain tumors are classified as grade 1 (the lowest grade) to 4 (the highest grade). According to the 2016 National Cancer Registry data, primary brain tumors are reported to occur in about 22.2 cases per 100,000 people per year, and about 25% of them are tumors called gliomas. The most common type of glioma is astrocytoma, which has a poor prognosis with a 5-year survival rate of 43% and 16% for grade 3 and 4, respectively.

On the other hand, it is said that 10% of the million cancers that occur annually will develop metastatic brain tumors. About half of metastatic brain tumors are metastases from lung cancer, followed by breast cancer and colorectal cancer.

The JCOG Brain Tumor Group was formed in 2003 and consists mainly of neurosurgical departments at university hospitals and core facilities across Japan. 41 facilities are participating as of January 2021, conducting clinical trials to develop standard and novel treatments for brain tumors.