Brain tumours, like most cancers, are groups of cells that grow together abnormally. As such, these tumours can be categorized into over 120 types of tumours. The most common form are gliomas, in which the cells originate in the glial (supportive) tissue, making up one third of all brain tumours diagnosed.
In the case of James, he was diagnosed with an astrocytoma glioma, the most common type of primary brain tumour within the group gliomas, making up about one third of all brain tumours diagnosed. These tumours grow a type of cell in the brain for which are called astrocytes, the most abundant cell in the brain. These cells support and protect the nerves and help to pass messages throughout the brain, a vital part in processing information.
Like most cancers, astrocytomas are divided into 4 types referred to as Grades. Grade 1, known as pilocytic, are slow growing, relatively contained, and are unlikely to spread in other parts of the brain. Once removed, the chances of recurrence are low. These tend to grow in the cerebellum, which controls balance, and sight.
Grade 2, which are diffuse, do not have well-defined edges as other types, making resection more difficult. These grow slowly as well, but may sometimes return as a Grade 3.
Grade 3 astrocytoma, the one in which James suffers, are fast-growing and often referred to as malignant (cancerous). In most cases, radiotherapy and sometimes chemotherapy is used. The course of radiotherapy may be over a several weeks. Grade 4 astrocytoma are usually called glioblastomas.