Brain Tumors and Brain Cancer
Brain tumors account for one in every 100 cancers diagnosed annually in the United States. Most malignant brain tumors and brain cancers have spread from other tumors in the body to the skull, including cancers of the breast and lung, malignant melanoma and blood cell cancers (such as leukemia and lymphoma). Some brain tumors start in the cells that support the nerve cells of the brain, where they can crowd out normal cells and spread to other locations in the body. Tumors can either destroy tissue or cause problems in other parts of the body because of the pressure the tumor puts on the brain.
Brain tumors can be grouped by the type of cell involved (such as meningioma, astrocytoma, lymphoma, etc.) or by the location in the brain. Metastasized cells may grow in one or several areas of the brain. Almost half of all brain tumors are non-cancerous (benign), slow growing and respond well to treatment.
Symptoms produced by brain tumors depend on their location, size, rate of growth and stage. Some nonmalignant brain tumors that grow slowly can become quite large before producing symptoms because there often is no swelling of the brain tissues. However, if because of their size or location, they cannot be easily removed, they can be as life threatening as malignant brain tumors.
Persons who have symptoms that do not go away should see their doctor immediately. In general, brain cancer symptoms include:
- Abnormal pulse and breathing rates can also occur
- Deep, dull headaches that recur often and persist without relief for long periods of time
- Difficulty walking or speaking
- Eyesight problems, including double vision
At the late stages of the disorder, dramatic changes in blood pressure may occur. Seizures are a common symptom of benign brain tumors and slow-growing cancers. Tumors can cause a part of the body to weaken or feel paralyzed. Hearing, sight and the sense of smell can be affected. Persons who display personality changes and are prone to confusion and unable to think clearly require immediate medical attention.
There are many different types of brain tumors, some of which can have several names. Even neuropathologists, who diagnose these brain tumors, are sometimes inconsistent in what they call them. Some of the most common types are:
- Acoustic neuroma
- Choroid plexus papilloma
- Glioblastoma multiforme
- Mixed, optic nerve and brain stem gliomas
- Pineal tumors
- Pituitary adenomas
- Primitive neuroectodermal tumors
- Vascular tumors
Causes and Risk Factors
Risk factors include exposure for long periods to ionizing radiation or to chemicals, such as vinyl chlorides, aromatic hydrocarbons, triazenes and N-nitroso compound. Generally, exposure occurs at the place of work. Genetically inherited diseases, such as tuberous sclerosis and von Hippel-Lindau disease, may make a person susceptible to brain tumors. Three out of five people who suffer from brain tumors are male. Brain tumors are most common in early or middle adult life, but they can appear at any age.
The patient's symptoms often indicate the presence of a brain tumor and where it is located. A doctor may perform a neurologic exam to determine if the patient's senses, reflexes, mental status and memory are working normally. The doctor may also order imaging tests, including computed tomography (CT) or magnetic resonance imaging (MRI) of the brain, to pinpoint the brain tumor and show its size.
A biopsy can then be performed to identify the type of brain tumor and whether it is malignant (cancerous). During a biopsy, a small amount of the cancerous tissue is taken and analyzed under a microscope. A biopsy can usually be done during surgery in which all or part of the brain tumor is removed. Tumors buried deep in the brain sometimes cannot be approached safely. In those cases, a biopsy procedure involves using three-dimensional needle technique in which special imaging equipment guides the placement of a needle to allow cells to be drawn into the needle.
Sometimes a spinal tap is done so that spinal fluid can be collected and examined for cancer cells. If the tumor is causing pressure in the brain, this procedure cannot be done because the sudden change in pressure in the skull could cause herniation (bulging of a membrane). Herniation is one of the most dangerous possible complications of a brain tumor and one that can cause serious breathing, heart rate and blood pressure problems. Unless it is caught early, herniation eventually results in coma and death.
When possible, brain tumors are removed through surgery. While many can be removed with little or no damage to the brain, others are located where surgical removal is difficult or impossible without destroying critical parts of the brain.
Brain damage caused by surgery can lead to partial paralysis, changes in sensation (feeling), weakness and poor thinking. Even so, removing a tumor is necessary when it threatens important brain structures. Even when it can't cure a malignancy, surgery can help reduce the size of the tumor, ease symptoms and help determine the type of tumor and best treatment.
Other treatments for brain tumors include: