A glioma such as a glioblastoma, also called glioblastoma multiforme, is a type of tumor that develops from the glial cells in the brain and central nervous system. Glial cells are supportive cell structures that bring nutrients and energy to the brain's nerve cells. NeuroTexas Institute describes glioblastomas as one of the most malignant gliomas. Glioblastoma occurs in adults and children.
Types of Glioma
There are three different types of glial cells that form gliomas: astrocytes, oligodendrocytes and ependymal cells. Glioblastomas are tumors that form from malignant glial astrocytes. The American Cancer Society states that glioblastomas are the most common type of primary brain tumor and the fastest growing. Glioblastomas can develop anywhere in the brain and spread throughout the brain and central nervous system.
Incidence of Glioblastomas
According to the National Cancer Institute (NCI), glioblastomas constitute approximately 15 percent of all brain tumors. The peak incidence of tumor onset is between 45 and 70 years of age. NCI statistical data from 2006 indicate that brain cancer and other nervous system cancers account for only 2 percent of all cancers among adults. However, in children, brain cancer and other nervous system cancers comprise the second most common incidence of cancer, at 3.2 percent for both boys and girls.
Diagnosis
A physician may form a clinical suspicion of glioblastoma based on patient presentation and history. A computerized tomography scan, or CT, or a magnetic resonance imaging scan, also known as an MRI, can identify the presence of a brain tumor. A biopsy will determine if the tumor is a glioblastoma.
Symptoms
A glioblastoma can develop anywhere in the brain, so symptoms will vary depending on the location of the tumor. Typically, the first symptoms experienced are related to increased pressure in the brain from the presence of the tumor. Symptoms may be mild and vague, such as headaches, nausea, blurred vision or drowsiness. However, initial symptoms can be as severe as a sudden onset of seizure activity, projectile vomiting and altered mental status.
Treatment
Results of many clinical trial case studies conducted through the NCI support the need for radiation therapy, chemotherapy and supportive care to improve the survival rate for patients with glioblastoma. When possible, surgical resection of glioblastoma tumors improves quality of life by decreasing symptoms. Treatment should continue with radiation and chemotherapy, for example, with temozolomide, which during clinical trials significantly increased the two-year survival rate of these patients.
Prognosis
The World Health Organization classification system for central nervous system tumors is used to guide treatment and establish prognosis. Grades range from Grade I to Grade IV; the higher the grade, the more advanced and aggressive the tumor is, which means a poorer prognosis. A glioblastoma is a Grade IV astrocytoma. At this grade, it may not be possible to remove the tumor surgically and it may be incurable. The NCI recommends that patients with such advanced brain tumors be candidates for clinical trials, which examine therapies such as hyperthermia, interstitial brachytherapy (implanted radiation) and intraoperative radiation therapy.
