Brain tumors can occur in two forms: benign (non-cancerous) and malignant (cancerous). Benign tumors can usually be removed and rarely grow back. Oncologists can tell the two types apart by looking at the edges of the tumor. Because the cells of benign tumors don't grow into nearby healthy tissue, the borders of the tumor are neat and easy to see. Benign brain tumors can be dangerous when they press on parts of the brain that control the function of other organs. A benign tumor on the brain stem, for instance, would eventually stop the heart and other automatic body functions.
Cancerous brain tumors are either primary (starting in brain tissue), or secondary (starting as a cancer elsewhere in the body and metastasizing--or migrating--to the brain).
Cancerous brain tumors are named for their origin and other factors. Oncologists use a grading system from I to IV depending on the degree of cellular abnormality seen under a microscope. More severe abnormalities get a higher grade from I to IV.
Gliomas
The most common type of cancerous brain tumors are gliomas, which start in the star-shaped glial cells of the brain. Glial cells provide support, structure and nutrition to the brain's workhorse nerve cells. Here are the most common types of glioma. Astrocytomas grow in glial cells called astrocytes. In adults, astrocytomas usually develop in the cerebrum. In children, they can grow in the brain stem, cerebrum and cerebellum. Brain stem glioma is found in the oldest part of the brain, which controls automatic functions such as heartbeat. They can strike adults and children. Ependymoma grows in cells that line the fluid-filled ventricles or the central canal of the spinal cord. They are usually diagnosed in children and young adults. Oligodendroglioma is a very rare tumor found in cells that make the fatty substance that covers and protects nerves and usually occur in the cerebrum. They grow slowly and rarely invade surrounding brain tissue. They are frequently diagnosed in middle-aged adults.
Non-glioma Cancerous Brain Tumors
Cancerous brain tumors also grow in other types of brain tissue. Here are some of the most common types. Medulloblastoma grows in the cerebellum, and is the most common type of brain tumor diagnosed in children. It is also called a primitive neuroectodermal tumor. Meningioma is found in the meninges, the membrane that protects the brain and spinal cord. It is usually slow growing and without symptoms. Schwannoma is a tumor that grows on the lining of the cranial nerve in the inner ear that controls hearing and balance. They are sometimes called acoustic neuromas. Schwannoma usually occurs in adults. Craniopharyngioma grows at the base of the brain near the pituitary gland, and typically occurs in children. Germ cell tumor of the brain occurs when germ cells, normally found in the ovaries and testis, appear in the brain because of a developmental defect during pregnancy. This type of tumor is almost always found in very young children. Germ cell tumors are also called germinoma. Pineal region tumor develops in or near the pineal gland, which is located between the cerebrum and the cerebellum. It is a very rare tumor.
Common Symptoms of Brain Tumors
Brain tumors press on other brain tissue and can cause a wide range of symptoms. Symptoms can be confused with other causes, such as head injuries and strokes. They include frequent and severe headaches, seizures, vomiting, loss of speech, loss of fine and gross motor skills, slurred speech, changes in personality, loss of appetite, mood swings and changes in the ability to think, learn, memorize, see and hear.
Surgical Treatment of Brain Tumors
Treatment of cancerous brain tumors depends on the age and overall health of the patient, type of tumor, how aggressive it is, the location of the tumor and whether or not the cancer has spread to other areas of the body. Options include surgery, radiation and chemotherapy, or a combination of the three. Treatment plans are designed for patients individually. Advances in surgery, such as robotic and laser techniques, have made brain surgery and removal of cancerous brain tumors much more survivable and improved results for patients in the last decade. After the tumor and a portion of surrounding healthy tissue are removed, they are examined by a pathologist to make sure nothing of the cancer has been left behind. Risks include infection, damage to surrounding muscles, nerves and blood vessels and recurrence of the cancer. Patients are often prescribed a course of physical therapy after surgery to help them regain full use of areas of their bodies that might have been affected by the tumor. Speech and physical therapy are common.
Chemotherapy and Radiological Treatments of Cancerous Brain Tumors
Chemotherapy is administered by an oncologist, and comprises a series of powerful intravenous drug treatments aimed at preventing the growth of cancer cells. Chemotherapy is often used before surgery to shrink the tumor, making surgery less invasive. After surgery, it is used as a safeguard to kill any remaining cancer cells. Chemotherapy kills cancer cells, but also affects hair, digestive tract cells and blood-forming cells. Loss of hair, nausea, loss of appetite, anemia and low energy are frequent side effects of chemotherapy. These side effects usually end after chemotherapy stops.
Radiation therapy is administered by a radiation oncologist, and comprises a series of series of high-energy C-rays applied to the site of the tumor. This treatment is given in small doses over several days, sometimes months. The most common side effects are loss of appetite, fatigue and damage to the skin and other soft tissue at the site of the treatment. Patients who undergo surgery near the site of radiation therapy sometimes are slow to heal because of damage to the blood vessels. Most side effects go away quickly after radiation therapy is over, but problems with slow healing may persist.
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