What is a brain tumor?

A brain tumor starts when cells in the brain change and grow out of control. As they continue to grow, they form a mass of cells that becomes a tumor. Brain tumors form in one of two ways:

• Primary brain tumor: This starts with an abnormal brain cell that grows in the brain.
• Metastatic (secondary) tumor: This starts as a cancer in another part of the body, such as the lungs or breast. It then spreads to the brain, where it forms a new tumor. The cancer cells in the brain still look like the cells where they first started, like the lung or breast. They don't look like mutated brain cells.

How common is brain cancer?

Primary brain tumors are relatively rare. Less than 1% of people are diagnosed with a primary brain tumor each year in the United States. According to the American Cancer Society, about 25,000 “malignant tumors of the brain or spinal cord will be diagnosed. These numbers would be much higher if benign tumors were also included.”

Secondary brain tumors are much more common than primary brain tumors in adults. Primary brain tumors are more common in children.

Brain tumors can cause damage by growing into and pushing on key areas of the brain. They can also cause problems if they block the flow of fluid around the brain. This fluid is called cerebrospinal fluid (CSF). This can lead to an increase in the pressure inside the skull. Some types of tumors can spread through the CSF to other parts of the brain or the spinal cord. 

A primary brain tumor can be malignant or benign.

A malignant primary tumor is more dangerous because it can grow quickly. It may grow into or spread to other parts of the brain or to the spinal cord. Malignant tumors are also sometimes called brain cancer.

A benign primary brain tumor is not cancer. Benign tumors can cause damage by growing into and pressing on other parts of the brain. But these tumors don't spread.

Overview

The type of brain tumor, the size of the tumor and its location within the brain are important. For instance, some benign brain tumors can be quite harmful. They can cause severe problems if in or near a key part of the brain. There are more than 100 types of brain tumors, including glioblastoma. They're often named by the type of brain cell or part of the brain where they start. Some of the more common types of primary brain tumors in adults include:

• Astrocytoma: This is the most common type of malignant brain tumor. Its name comes from the star-shaped brain cells that make up the tumor. These tumors can grow anywhere in the brain.
• Meningioma: This is the most common type of brain tumor in adults. They are usually not cancer (benign). These tumors start in the lining that covers the brain. They can cause serious problems when they press on vital parts of the brain or grow into nearby brain tissue. In rare cases, they can become cancer. They usually grow slowly and are only found by accident when an MRI is done for some other reason.
• Oligodendroglioma: These brain tumors form in the cells that make the fatty lining that covers nerves (called myelin).

Astrocytomas are common in children, as they are in adults. But they are less likely to be cancer. These are other common primary brain tumors in children:

• Medulloblastoma: This tumor is cancer. It forms in the cerebellum, the back part of the brain near the spinal cord. It can spread to the spinal cord and cause spinal fluid to build up into the brain (hydrocephalus).
• Ependymoma: This rare tumor is found in young children and young adults. It may or may not be cancer. It starts in the lining around fluid-filled areas of the brain (called the ventricles).
• Brain stem glioma: This tumor starts in the base of the brain. It often spreads through the normal tissue.

Metastatic or secondary brain tumors are more common than primary brain tumors in adults. These tumors are usually found in more than one part of the brain. The most common cancers that spread to the brain are lung, breast, colon, bladder, kidney, melanoma skin cancers and leukemia and lymphoma.

Symptoms

What are the signs and symptoms of a brain tumor?

Symptoms of a brain tumor depend on how big the tumor is and where it is in the brain. Warning signs of a brain tumor may also be affected by increased pressure in the brain from the mass or from swelling. They may include:

• Changes in speech, vision, hearing, memory or personality
• Dizziness
• Feeling tired all the time (fatigue)
• Headache
• Nausea or vomiting
• Problems with balance or walking
• Seizures
• Weakness or numbness in the arms, legs or face

Risk Factors

What causes brain tumors?

Most brain tumor causes start with no known risk factors. But some factors may increase your risk for brain tumors, such as:

• Radiation exposure. People who have had radiation to the head are at higher risk for brain tumors. Most often this exposure comes from radiation therapy used to treat another type of cancer, like leukemia during childhood.
• Certain inherited syndromes. People who are born with certain syndromes, such as neurofibromatosis, von Hippel-Lindau disease, Li-Fraumeni syndrome, and tuberous sclerosis, have an increased risk of brain tumors.
• Family history of brain tumors. Most people with brain tumors don’t have a family history of the disease. But in rare cases, tumors can run in families.
• Weak immune system. People who have a weak immune system have a higher risk of developing central nervous system lymphoma. This includes people who have AIDS or who have had an organ transplant.

Diagnosis

How is brain cancer diagnosed?

Brain tumor diagnosis starts with your provider asking you questions. You'll be asked about your health history, your symptoms, risk factors and family history of disease.

A physical exam will also be done. You will likely be checked for possible signs of brain or spinal cord problems. So the exam will test things like your reflexes, muscle strength, sensation, eye and mouth movement, vision, coordination and alertness.

What tests might I need?

You may need one or more of these imaging tests:

• Angiogram
• Brain tumor biopsy
• CT scan or CT angiogram
• Diffusion tensor imaging
• Electroencephalogram
• Functional MRI
• Lumbar puncture (spinal tap)
• Magnetic resonance imaging (MRI)
• Magnetic resonance spectroscopy
• Magnetic resonance angiography and magnetic resonance venography
• Positron emission tomography scan
• Vision and hearing tests

Treatment

Diagnosis usually begins with a high-quality MRI. The scan allows your providers to diagnose the type of tumor. In some cases, monitoring is all that is needed. In other situations, treatment may focus on radiation or Gamma Knife treatment.

Rest assured, your team will explore all options available and recommend the one that will give you the best long-term outlook.

What are the types of brain cancer treatment?

Treatment will depend on:

• The type, size and characteristics of the tumor cells and blood vessels
• The aggressiveness of the tumor
• Your age and general health
• Symptoms that are related to the tumor

Certain types of brain surgery involve no incision and are painless. Stereotactic radiosurgery uses narrow beams of radiation generated from different angles to give highly-focused radiation to a brain tumor. This helps preserve the healthy tissues surrounding the brain tumor. Treatment takes about two hours, and patients can often go home the same day.  

Other brain tumor treatments include:

• Surgery. Surgery is used to remove the tumor while leaving as much of the brain as possible intact. It's often the first step in treatment for most brain tumors. Removing the tumor (resection) is usually done if the tumor can be removed safely. Surgery gives the healthcare team an exact diagnosis. It also reduces the tumor size. In some cases, the surgeon can’t remove the whole tumor. This may be because it’s near vital parts of the brain. Or it may be growing into the brain. If the tumor is in an area of the brain that can’t be reached safely, a small amount of tissue is still taken out for testing (biopsy).
• Radiation therapy. The goal of radiation is to kill cancer cells. This is done using X-rays, gamma rays, or proton beams. It may be done to shrink a tumor before surgery. Or it may be done to kill any cancer cells that may be left after surgery. Radiation therapy might be used as the main treatment if surgery isn't a choice. It can also help relieve symptoms caused by a tumor.
• Chemotherapy. Chemotherapy may be used after surgery or biopsy. Its goal is to reduce the chance that the cancer will grow, spread, or come back. In many cases, chemotherapy is taken by mouth as pills. But these medicines may also be given as a liquid put into your blood through a vein (IV) or put right into the cerebrospinal fluid around your brain. If you can’t have surgery, you may still get chemotherapy. You might also get it along with radiation therapy. Chemotherapy may be used if the cancer comes back after treatment.
• Targeted therapy. Newer medicines target different parts of cancer cells or nearby blood vessels. They work differently from standard chemotherapy medicines. A few targeted medicines are used to help treat certain kinds of brain tumors. They're usually used when surgery is not a choice or the tumor comes back after treatment.
• Other medicines. Other medicines might be used to help relieve or prevent symptoms caused by the tumor or its treatment. For instance, you might be given medicines to help prevent seizures or help control swelling in the brain. You may also receive antinausea medicine or medicine to treat chemotherapy-induced anemia.

What is the brain cancer survival rate?

According to the American Cancer Society, the five-year survival rate for brain cancer varies based on age. For most common brain cancers, the five-year survival rate is between 60% and 90%.