A brain tumor is a mass or growth of abnormal cells in the brain.
Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your brain (primary brain tumors), or cancer can begin in other parts of your body and spread to your brain (secondary, or metastatic, brain tumors).
How quickly a brain tumor grows can vary greatly. The growth rate as well as the location of a brain tumor determines how it will affect the function of your nervous system.
Brain tumor treatment options depend on the type of brain tumor you have, as well as its size.
The signs and symptoms of a brain tumor vary greatly and depend on the brain tumor’s size, location, and rate of growth.
General signs and symptoms caused by brain tumors may include:
- change in pattern of headaches
- Unexplained nausea or vomiting
- Vision problems, such as blurred vision, double vision or loss of peripheral vision
- Gradual loss of sensation or movement in an arm or a leg
- Difficulty with balance
- Speech difficulties
- Confusion in everyday matters
- Personality or behavior changes
- Seizures, especially in someone who doesn’t have a history of seizures
- Hearing problems
Brain tumors that begin in the brain
Primary brain tumors originate in the brain itself or in tissues close to it, such as in the brain-covering membranes (meninges), cranial nerves, pituitary gland or pineal gland.
Primary brain tumors begin when normal cells acquire errors (mutations) in their DNA. These mutations allow cells to grow and divide at increased rates and to continue living when healthy cells would die. The result is a mass of abnormal cells, which form a tumor.
In adults, primary brain tumors are much less common than are secondary brain tumors, in which cancer begins elsewhere and spreads to the brain.
Many different types of primary brain tumors exist. Each gets its name from the type of cells involved. Examples include:
- Gliomas. These tumors begin in the brain or spinal cord and include astrocytoma, ependymomas, glioblastomas, oligoastrocytomas and oligodendrogliomas.
- Meningiomas. A meningioma is a tumor that arises from the membranes that surround your brain and spinal cord (meninges). Most meningiomas are noncancerous.
- Acoustic neuromas (schwannomas). These are benign tumors that develop on the nerves that control balance and hearing leading from your inner ear to your brain.
- Pituitary adenomas. These are mostly benign tumors that develop in the pituitary gland at the base of the brain. These tumors can affect the pituitary hormones with effects throughout the body.
- Medulloblastomas. These are the most common cancerous brain tumors in children. A medulloblastoma starts in the lower back part of the brain and tends to spread through the spinal fluid. These tumors are less common in adults, but they do occur.
- Germ cell tumors. Germ cell tumors may develop during childhood where the testicles or ovaries will form. But sometimes germ cell tumors affect other parts of the body, such as the brain.
- Craniopharyngiomas. These rare, noncancerous tumors start near the brain’s pituitary gland, which secretes hormones that control many body functions. As the craniopharyngioma slowly grows, it can affect the pituitary gland and other structures near the brain.
Cancer that begins elsewhere and spreads to the brain
Secondary (metastatic) brain tumors are tumors that result from cancer that starts elsewhere in your body and then spreads (metastasizes) to your brain.
Secondary brain tumors most often occur in people who have a history of cancer. But in rare cases, a metastatic brain tumor may be the first sign of cancer that began elsewhere in your body.
In adults, secondary brain tumors are far more common than are primary brain tumors.
Any cancer can spread to the brain, but common types include:
- Breast cancer
- Colon cancer
- Kidney cancer
- Lung cancer
In most people with primary brain tumors, the cause of the tumor is not clear. But doctors have identified some factors that may increase your risk of a brain tumor.
Risk factors include:
- Exposure to radiation. People who have been exposed to a type of radiation called ionizing radiation have an increased risk of brain tumors. Examples of ionizing radiation include radiation therapy used to treat cancer and radiation exposure caused by atomic bombs.
- Family history of brain tumors. A small portion of brain tumors occurs in people with a family history of brain tumors or a family history of genetic syndromes that increase the risk of brain tumors.
Treatment for a brain tumor depends on the type, size and location of the tumor, as well as your overall health and your preferences.
If the brain tumor is located in a place that makes it accessible for an operation, your surgeon will work to remove as much of the brain tumor as possible.
In some cases, tumors are small and easy to separate from surrounding brain tissue, which makes complete surgical removal possible. In other cases, tumors can’t be separated from surrounding tissue or they’re located near sensitive areas in your brain, making surgery risky. In these situations your doctor removes as much of the tumor as is safe.
Even removing a portion of the brain tumor may help reduce your signs and symptoms.
Surgery to remove a brain tumor carries risks, such as infection and bleeding. Other risks may depend on the part of your brain where your tumor is located. For instance, surgery on a tumor near nerves that connect to your eyes may carry a risk of vision loss.
Radiation therapy uses high-energy beams, such as X-rays or protons, to kill tumor cells. Radiation therapy can come from a machine outside your body (external beam radiation), or, in very rare cases, radiation can be placed inside your body close to your brain tumor (brachytherapy).
External beam radiation can focus just on the area of your brain where the tumor is located, or it can be applied to your entire brain (whole-brain radiation). Whole-brain radiation is most often used to treat cancer that spreads to the brain from some other part of the body and forms multiple tumors in the brain.
A newer form of radiation therapy using proton beams is being studied for use in people with brain tumors. For tumors that are very close to sensitive areas of the brain, proton therapy may reduce the risk of side effects associated with radiation. But proton therapy hasn’t proved to be more effective than standard radiation therapy with X-rays.
Side effects of radiation therapy depend on the type and dose of radiation you receive. Common side effects during or immediately following radiation include fatigue, headaches, memory loss and scalp irritation.
Stereotactic radiosurgery is not a form of surgery in the traditional sense. Instead, radiosurgery uses multiple beams of radiation to give a highly focused form of radiation treatment to kill the tumor cells in a very small area. Each beam of radiation isn’t particularly powerful, but the point where all the beams meet — at the brain tumor — receives a very large dose of radiation to kill the tumor cells.
There are different types of technology used in radiosurgery to deliver radiation to treat brain tumors, such as a Gamma Knife or linear accelerator.
Radiosurgery is typically done in one treatment, and in most cases you can go home the same day.
Chemotherapy uses drugs to kill tumor cells. Chemotherapy drugs can be taken orally in pill form or injected into a vein (intravenously). The chemotherapy drug used most often to treat brain tumors is temozolomide (Temodar), which is taken as a pill. Many other chemotherapy drugs are available and may be used depending on the type of cancer.
Chemotherapy side effects depend on the type and dose of drugs you receive. Chemotherapy can cause nausea, vomiting and hair loss.
Tests of your brain tumor cells can determine whether chemotherapy will be helpful for you. The type of brain tumor you have also is helpful in determining whether to recommend chemotherapy.
Targeted drug therapy
Targeted drug treatments focus on specific abnormalities present within cancer cells. By blocking these abnormalities, targeted drug treatments can cause cancer cells to die.
Targeted therapy drugs are available for certain types of brain tumors, and many more are being studied in clinical trials. Many different forms of targeted therapy are being developed.
Rehabilitation after treatment
Because brain tumors can develop in parts of the brain that control motor skills, speech, vision and thinking, rehabilitation may be a necessary part of recovery. Depending on your needs, your doctor may refer you to:
- Physical therapy to help you regain lost motor skills or muscle strength
- Occupational therapy to help you get back to your normal daily activities, including work, after a brain tumor or other illness
- Speech therapy with specialists in speech difficulties (speech pathologists) to help if you have difficulty speaking
- Tutoring for school-age children to help kids cope with changes in their memory and thinking after a brain tumor