A glioma is a primary tumor found in the brain or central nervous system which includes the spinal cord and nerves throughout the body.
Most commonly diagnosed gliomas are found in the brain. Some are malignant and some are benign.
Anatomy of The Brain
The brain is composed of the cerebrum, also known as the higher brain; the cerebellum or lower brain; and the brain stem. The cerebrum is made up of four major lobes which are the frontal lobe, the parietal lobe, the occipital lobe and the temporal lobe. Each area has a specific set of functions.
Gliomas can occur in any area of the brain and the malignant ones are classified into four grades, I-IV. The easiest to treat are grades I and II. Grades III and IV are much more difficult to treat. About 22,000 Americans are diagnosed with malignant gliomas each year. This represents about 2% of all cancers. Approximately 13,000 die each year.
No Cure
There is no cure for malignant gliomas. Treatment consists of surgery, radiation and chemotherapy. Surgery is not often an option. Malignant gliomas grow when genes in the cells that provide support tissue to the neurons go haywire. Neurons are the cells that do the work in the brain and send signals to the various parts of the body.
Because the malignant glioma intertwines itself with healthy neurons it is almost impossible to remove surgically. It is difficult to determine a distinct border between the malignant cells and healthy tissue. The prognosis is poor and worsens with age. The life expectancy is about 12 months, but some live as long as 18 months.
Surgery can damage healthy neurons and therefore cause damage to the brain function in that area. It often only offers the patient a few more months of life and the quality of life can be dramatically affected if the brain is damaged.
Radiation can shrink the tumor and lessen the effects on the brain. Chemotherapy can kill some of the tumor cells but it has not yet proven to be effective at managing the disease. A new drug, temozolomide, is being used in combination with radiation as it appears to improve the effectiveness of killing the malignant cells.
Signs and Symptoms
Brain cancers are the least painful of all cancers although a major headache is often one of the first signs noted. Seizures, one sided weakness, visual and speech disturbances should also be investigated as possible signs of brain tumors. A CAT scan, MRI and brain biopsy are the usual diagnostic tools once a tumor is suspected.
Any brain tumor will irritate the brain tissue and interfere with the function of that part of the brain in much the same way a stroke affects the brain function. Strokes however often affect a much larger area of the brain.
Kennedy's Tumor is Inoperable
In the instance of Senator Edward Kennedy (D-MA), a glioma in the left parietal lobe typically affects such functions as the ability to write, read, and do math. Speech may be impaired and the ability to understand speech. Surgery would most certainly cause damage to these functions.
Much less is known about the parietal lobe than other areas of the brain. It has two major functional regions. One controls sensation such as pain, temperature and touch. The other is the integration of sensory input such as the relationship of numbers and the manipulation of objects and spacial relationships.
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