Brain Cancer (Brain Tumor)
What is a brain tumor?
A brain tumor is an abnormal growth or mass of cells in or around the brain. It is also called a central nervous system tumor.
Brain tumors can be malignant (cancerous) or benign (not cancerous). Some tumors grow quickly; others are slow-growing.
Only about one-third of brain tumors are cancerous. But whether they are cancerous or not, brain tumors can impair brain function if they grow large enough to press on surrounding nerves, blood vessels and tissue.
Tumors that develop in the brain are called primary tumors. Tumors that spread to the brain after forming in a different part of the body are called secondary tumors or metastatic tumors. This article focuses on primary tumors. There are more than 100 types of primary brain and spinal cord tumors.
How common are brain tumors?
Doctors diagnose brain tumors in about 85,000 people in the U.S. every year. Of those tumors, roughly 60,000 are benign, and about 25,000 are malignant.
Who is affected by brain tumors?
Brain tumors occur more often in men than women. Although they are most common among older adults, they can develop at any age. Brain tumors are the leading cause of cancer-related death in children under age 14.
What are the types of brain tumors?
Doctors classify brain and central nervous system tumors based on where they form and the kind of cells they involve.
Brain tumors that are usually benign include:
- Acoustic neuroma: These tumors occur on the vestibular nerve (the nerve that leads from the inner ear to the brain). Acoustic neuromas are also called vestibular schwannomas.
- Gangliocytoma: These central nervous system tumors form in neurons (nerve cells).
- Meningioma: These are the most common type of primary brain tumors. Meningiomas develop slowly. They form in the meninges, the layers of tissue that protect the brain and spinal cord. In rare cases, a meningioma can be malignant.
- Pineocytoma: These slow-growing tumors form in the pineal gland, which is located deep in the brain and secretes the hormone melatonin.
- Pituitary adenoma: These tumors form in the pituitary gland, which is located at the base of the brain. The pituitary gland makes and controls hormones in the body. Pituitary adenomas are usually very small.
- Chordoma: These slow-growing tumors typically begin at the base of the skull and the bottom part of the spine. They are mostly benign (not cancerous).
Cancerous brain tumors include:
- Glioma: These tumors develop in glial cells, which surround and assist nerve cells. Two-thirds of cancerous primary brain tumors are gliomas. Types of gliomas include:
- Medulloblastoma: Medulloblastomas are fast-growing tumors that form at the base of the skull. These are the most common cancerous brain tumors in children.
Symptoms and Causes
What causes a brain tumor?
Doctors are not sure what causes most brain tumors. Mutations (changes) or defects in genes may cause cells in the brain to grow uncontrollably, causing a tumor.
The only known environmental cause of brain tumors is having exposure to large amounts of radiation from X-rays or previous cancer treatment. Some brain tumors occur when hereditary conditions are passed down among family members.
What are the symptoms of a brain tumor?
Some people with a brain or central nervous system tumor have no symptoms. In some cases, doctors discover a tumor during treatment for another issue.
As a brain tumor grows and presses on surrounding nerves or blood vessels, it may cause symptoms. Signs and symptoms of a brain tumor vary depending on the tumor’s location and type, size and what the affected part of the brain controls. They can include:
- Headaches that are ongoing or severe; or that occur in the morning or go away after vomiting.
- Behavior or personality changes.
- Difficulty with balance or coordination.
- Trouble concentrating.
- Nausea and vomiting.
- Numbness, weakness or tingling in one part or side of the body or face.
- Problems with hearing, vision or speech.
- Unusual sleepiness.
- Trouble with memory, thinking, speaking or understanding language.
Diagnosis and Tests
How is a brain tumor diagnosed?
Doctors use several tests to confirm the presence of a brain tumor. These tests include:
- Physical exam and medical history: Your doctor will perform a general health exam, looking for signs of diseases or illnesses. Your doctor will also ask questions about past and current health conditions, surgeries and medical treatments and family history of disease.
- Blood test: To check for tumor markers (substances secreted into blood by tumors) that are linked to certain types of tumors.
- Biopsy: Through a small hole in the skull, a doctor uses a needle to take a sample of tissue from the tumor. A laboratory studies the sample to identify details from the tumor, including how fast it is growing and whether it is spreading.
- Imaging tests: CTs, MRIs, SPECTs and PET scans help doctors locate the tumor and determine if it is cancerous or benign. Your doctor may also look at other parts of the body, such as the lungs, colon or breasts, to identify where the tumor started.
- Neurological exam: During a neurological exam, your doctor will look for changes in your balance, coordination, mental status, hearing, vision and reflexes. These changes can point to the part of your brain that may be affected by a tumor.
- Spinal tap: A doctor uses a small needle to remove fluid from around the spine. A laboratory examines this fluid to look for cancer cells, which can indicate a malignant tumor somewhere in the central nervous system.
When brain tumors are cancerous, doctors classify the tumors into four grades (1 [least malignant/slow growing] through 4 [most malignant/fast growing]) as part of the diagnosis. The grade assigned to a tumor indicates how fast it's growing and its likelihood of spreading. By grading the tumor, your doctor can determine the most effective treatment options.
Management and Treatment
What are the treatments for a brain tumor?
Brain tumor treatment depends on the tumor’s location, size and type. Doctors often use a combination of therapies to treat a tumor.
Your treatment options might include:
- Surgery: When possible, surgeons remove the tumor. They work very carefully, sometimes doing surgery when you are awake, to minimize damage to functional areas of the brain.
- Radiation therapy: High doses of X-rays destroy brain tumor cells or shrink the tumor. Some people have radiation before surgery to shrink a brain tumor so that the surgeon can remove less tissue.
- Chemotherapy: Anti-cancer drugs kill cancer cells in the brain and throughout the body. You might receive chemotherapy through an injection into a vein or take as a pill. In some cases, doctors use chemotherapy before surgery to make the tumor smaller. Your doctor may recommend chemotherapy after surgery to kill any cancer cells left behind or to prevent remaining tumor cells from growing.
- Immunotherapy: Immunotherapy, also called biological therapy, is a type of treatment that uses your body's own immune system to fight cancer. The therapy mainly consists of stimulating the immune system to help it do its job more effectively.
- Targeted therapy: Drugs target specific features in cancer cells without harming healthy cells. Your doctor may recommend targeted therapy if you have trouble tolerating the side effects of chemotherapy, such as fatigue and nausea.
- Laser thermal ablation: This treatment uses lasers to heat and destroy tumor cells.
- Watchful waiting/active surveillance: A doctor closely monitors the tumor for signs of growth with regular testing, but does not take any other action.
What are the complications associated with a brain tumor?
Some people with a brain tumor — whether it is benign or malignant — experience complications as the tumor grows and presses on surrounding tissue. These complications include:
- Decreased alertness.
- Difficulty speaking.
- Faster or slower breathing and pulse rates.
- Numbness that interferes with feeling pressure, heat or cold on the body.
- Weakness or inability to move a leg or arm on one side of the body.
- Vision, hearing and smelling problems.
How can you prevent a brain tumor?
You cannot prevent a brain tumor. You can reduce your risk of developing a brain tumor by avoiding environmental hazards such as smoking and excessive exposure to radiation.
Who is at risk of developing a brain tumor?
People who have higher risk for brain tumors include those who have:
- Family history of cancer.
- Genetic mutation that causes abnormal cell growth.
- Long-term exposure to radiation from X-rays or treatment for other cancers.
- Exposure to certain chemicals (possible cause).
Outlook / Prognosis
What's the outlook for people with a brain tumor?
The outcome for people with brain tumors varies greatly. Factors that can affect prognosis include the tumor’s type, grade, and location; successful removal of all of the tumor; and your age and overall health.
In many people, doctors can successfully treat a brain tumor. Other people live active and fulfilling lives with brain tumors that do not cause symptoms.
In some people, brain tumors can recur (return) after treatment. These people may need to continue treatments, including chemotherapy or radiation, to keep the tumor from growing or spreading. After brain tumor treatment, you should follow up with your doctor regularly.
When should I see a healthcare provider about a possible brain tumor?
Contact your healthcare provider if you experience signs and symptoms of a brain tumor.
What questions should I ask my doctor?
If you have a brain tumor, you may want to ask your doctor:
- Is the tumor malignant or benign?
- What kind of tumor do I have?
- What type of treatment is best for me?
- Will my treatment cause side effects?