A is a type of primary
Central Nervous System (CNS)
Tumor that arises from
Glial Cell s. The most common site of involvement of a glioma is the brain, but they can also affect the spinal cord, or any other part of the CNS, such as the optic nerves.
Gliomas are named according to the specific type of cell they most resemble. The main types of gliomas are:
Gliomas are further categorized according to their
Grade , which is determined by
Pathologic evaluation of the tumor.
- Low grade gliomas are well-differentiated, slower growing, biologically less aggressive, and portend a better prognosis for the patient.
- High grade gliomas are undifferentiated or Anaplastic , fast growing and can invade adjacent tissues, and carry a worse prognosis.
There are numerous grading systems, but the most commonly used system is the
World Health Organization (or WHO) grading system for astrocytomas. The WHO system assigns astrocytomas a grade from 1 to 4, with 1 being the least aggressive and 4 being the most aggressive. Various types of astrocytomas are given corresponding WHO grades.
:
The prognosis is worst for Grade 4 gliomas, with an average survival time of 12 months. Overall, few patients survive beyond 3 years.
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The gliomas can also be roughly classified according to their location:
Symptoms of gliomas depend on which part of the central nervous system is affected. A brain glioma can cause
Headaches ,
Nausea and
Vomiting ,
Seizures , and
Cranial Nerve disorders as a result of increased intracranial pressure. A glioma of the
Optic Nerve can cause visual loss. Spinal cord gliomas can cause
Pain ,
Weakness or
Numbness in the extremities. Gliomas do not metastasize by the bloodstream, but they can spread via the
Cerebrospinal Fluid and cause "drop metastases" to the spinal cord.
High grade gliomas are highly vascular tumors and have a tendency to infiltrate. They have extensive areas of
Necrosis and
Hypoxia . Often tumor growth causes a breakdown of the
Blood-brain Barrier in the vicinity of the tumor. As a rule, high grade gliomas almost always grow back even after complete surgical excision.
On the other hand, low grade gliomas grow slowly, often over many years, and can be followed without treatment unless they grow and cause symptoms.
Treatment for brain gliomas depends on the location and the grade. Often, treatment is a combined approach, using surgery,
Radiation Therapy , and
Chemotherapy . The radiation therapy is in the form of external beam radiation or the
Stereotactic approach using
Radiosurgery . Spinal cord tumors can be treated by surgery and radiation.
Gene Therapy using lytic viruses or prodrug converting retroviruses and adenoviruses is another new development for the treatment of gliomas.
Temozolomide is a chemotherapeutic drug that is able to cross the
Blood-brain Barrier effectively and is being used in therapy. A small number of low-scale clinical studies have shown possible links between prescription of
Carphedon and improvement in a number of
Encephalopathic conditions, including lesions of cerebral blood pathways, and certain types of glioma.
