Gliomas are a type of tumor that develop in the brain and spinal cord from glial cells. Glial cells are responsible for a variety of different nerve cell functions and are often described as “gluey.” While glioblastoma tumors are one of the more common type of glioma, there are several other varieties as well.
The location, size, and type of tumor all play a role in the malignancy, growth, and prognosis. Tumors are rated in “grades” of I (one) through IV (four), one being the most benign and four being the most malignant. Each type of glioma varies in the way it affects the brain, efficaciousness and type of treatment.
Pilocytic Astrocytomas
Pilocytic astrocytomas are more common in children than adults. These tumors are typically benign, slow growing, and form in the brainstem or cerebellum. Sometimes, these tumors are small and never grow, and doctors opt to simply keep an eye on them, especially in cases where it would be more dangerous to perform surgery.
In cases where it’s best to remove the tumor, surgery is an option. Radiation may also be used if the tumor forms in places it is particularly difficult to perform operate on, if the tumor regrows after surgery, or if parts of the tumor not removed by surgery. Pilocytic astrocytomas are considered a grade I tumor.
Low-Grade Gliomas
Other types of astrocytoma, as well as oligodendroglioma, and oligoastrocytoma form most often in the brains of adults between the ages of 20 to 50. Even when treatment is effective, these often return as a higher-grade tumor. If the tumor does not get bigger or develop into a higher grade, doctors may opt for observation.
If it is possible to remove the tumor without affecting brain function, surgery is often an extremely effective option. Radiation may be used when surgery is not possible, in tandem with surgery, to avoid recurrence, or to keep parts of the tumor that were not removable by surgery from growing. Chemotherapy is used only in extremely high-risk, aggressive cases. Low-grade gliomas are generally a grade II.
Malignant Gliomas
The anaplastic forms of astrocytoma, oligodendroglioma, and some oligoastrocytoma are more dangerous forms of glioma tumors. They are very aggressive and grow quickly. Additionally, because they produce tentacle-like appendages, surgery can be very difficult, although it is often the best choice of treatment. Regardless of whether or not surgery is an option, both radiation and chemotherapy are normally used as additional treatments, in part because these grade III tumors recur very often.
Glioblastoma Multiforme
Glioblastoma is the most aggressive and malignant of the gliomas. It is also the most common type of primary brain tumor, which means that it appears as a grade IV and grows quickly. Secondary tumors start out as a grade II or III, and then slowly become grade IV. It occurs most commonly in those between ages 60 and 80. When it does appear in those under the age of 45, it is generally the secondary form. It’s treatment is similar to that of low-grade gliomas, including the surgical difficulties of its tentacles. Recurrence is common, and the median survival rate is about two to three years.
