Brain metastasis is cancer that started in another part of the body and spread to the brain. It’s sometimes called secondary brain cancer or a metastatic brain tumour. Brain metastasis is not the same as cancer that starts in the brain (called primary brain cancer). Brain metastases are much more common than primary brain cancer.
Some kinds of cancer are more likely to spread to the brain than others. The most common types of cancer that spread to the brain are:
Cancer can spread to any part of the brain. The most common site of brain metastases is the cerebrum, which is the largest and top part of the brain. Less often, cancer spreads to the cerebellum and brain stem. Sometimes there is only a single brain tumour, but most people develop many brain metastases.
Cancer can also spread to the meninges. This is called leptomeningeal metastasis or meningeal carcinomatosis.
The symptoms of brain metastases vary depending on which part of the brain is affected. Other health conditions can cause the same symptoms as brain metastases. See your doctor if you have these symptoms.
Other signs and symptoms of brain metastases include:
- nausea and vomiting
- weakness or numbness in parts of the body, such as the face, arms or legs
- problems with memory and confusion
- changes in behaviour and personality
- problems with balance and coordination
- loss of bladder or bowel control (called incontinence)
- problems with speech
- problems with swallowing
The following tests may be used to diagnose brain metastases. Many of the same tests can help your healthcare team plan treatment and monitor brain metastases.
Health history and physical exam
Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past. In taking a health history, your doctor will ask questions about a personal history of symptoms that suggest brain metastases.
A physical exam allows your doctor to look for any signs of brain metastases. During a physical exam, your doctor may test your reflexes and check the feeling and strength you have in your arms and legs. The doctor may also look into your eyes using a special tool with a light (called ophthalmoscope) to see if the nerve at the back of the eye is swollen.
Find out more about physical exam.
Blood tests are usually done to check your general health and find out how some organs are working. The blood tests done during diagnosis include a complete blood count (CBC), an electrolyte panel and liver function tests.
Find out more about a complete blood count (CBC).
Magnetic resonance imaging (MRI)
MRI is an imaging test used to check for tumours in the brain. It is usually the first test done to check the reason for symptoms like headaches and seizures. It can identify the number, location and size of metastases.
Find out more about MRI.
Computed tomography (CT) scan
If an MRI can’t be done, a CT scan is used to check for tumours in the brain. An MRI can’t be used when there are certain metal devices inside the body, like a pacemaker.
Find out more about CT scan.
A biopsy is the removal of cells or tissues so they can be examined under a microscope. If you have a history of cancer, doctors can often diagnose brain metastasis based on the results of imaging tests so a biopsy isn’t usually needed. A biopsy may be done after imaging tests if you have never had cancer, or if the doctor thinks that there might not really be brain metastases.
If you need to have a brain biopsy, you are usually referred to a neurosurgeon. The neurosurgeon decides which type of biopsy will be best for your situation. An excisional biopsy or stereotactic biopsy may be used.
Find out more about biopsy.
If brain metastases are found before the primary cancer is diagnosed, the doctor may order tests to find out where the cancer started. Other tests may also be used to check for metastatic cancer in other parts of the body. These tests may include:
Treatments and supportive therapies
If you have brain metastases, your healthcare team will create a treatment plan just for you. It will be based on your needs and usually includes a combination of different treatments. Treatments can control and slow the growth of brain metastases, but the metastases usually don’t go away completely. They can also manage or prevent problems caused by brain metastases. These are sometimes called supportive therapies.
When deciding which treatments and supportive therapies to offer for brain metastases, your healthcare team will consider:
- where the cancer started
- your symptoms
- how well you can do daily activities (called performance status)
- how many metastases are in the brain and their size
- where the metastases are within the brain and spinal cord
- if you have metastases in other parts of the body
- the prognosis
- your personal preferences
You may be offered the following treatments and supportive therapies for brain metastases.
Corticosteroids are medicines used to reduce swelling and pressure in and around the brain. They are often the first supportive therapy given to manage symptoms of brain metastases such as headaches and neurologic problems. Corticosteroids can be used alone or along with other treatments like radiation therapy and surgery. They are given intravenously (through a needle into a vein) or orally (as a pill by mouth).
The most common corticosteroid used for brain metastases is dexamethasone (Decadron). It is usually given at least twice a day until symptoms are relieved. Then the dose of dexamethasone is slowly lowered to prevent long-term side effects.
Side effects of corticosteroids will depend mainly on the dose and the length of treatment. Common side effects of corticosteroids, including dexamethasone, are sleep problems, increased appetite, fluid buildup in the legs, arms or face, weight gain, high blood sugar levels, infection, mood changes and skin problems like rash or acne.
External beam radiation therapy is a common treatment for brain metastasis. It can be given to the whole brain or to very specific areas of the brain. Radiation therapy can be used alone or in combination with other treatments such as surgery. Dexamethasone is usually given before and after radiation therapy.
Whole-brain radiation therapy (WBRT) is standard treatment when there are many metastases in the brain. External beam radiation therapy is used for WBRT. Radiation is directed through the scalp and skull to the entire brain. WBRT may be given before or after surgery is done to remove a single metastasis. How long WBRT is used depends on the number of metastases, how severe symptoms are, other treatments given and other factors. It is usually given once a day for 5 or 10 days.
Stereotactic radiation therapy may be used when there are 1–3 small brain metastases. This is a type of external beam radiation that delivers one high dose of radiation to a very specific area of the brain. It avoids treating healthy brain tissue around the tumour with radiation. How many sessions of stereotactic radiation therapy are used depends on the size, location and number of metastases being treated, as well as other factors.
Side effects of radiation therapy will depend mainly on the type of radiation therapy, the area of the brain being treated and the length of treatment. Common side effects of radiation therapy to the brain are hair loss, fatigue and memory problems.
Surgery is a standard treatment when there is one brain metastasis, it can be safely removed and the primary cancer is controlled or stable. Sometimes surgery will be done to remove more than one tumour if there are only a few tumours or they are close together. Whole-brain radiation therapy is often done after surgery.
The type of surgery done for brain metastasis is called a craniotomy. The neurosurgeontemporarily removes part of the skull so they can reach the brain and remove the metastasis.
Side effects of surgery will depend mainly on the location of brain metastases. They include bleeding, swelling of the brain and seizures.
Anticonvulsants are medicines used to control seizures. They are also called antiseizure or anti-epileptic drugs. People with brain metastases who have seizures at diagnosis or develop seizures during treatment are usually started on anticonvulsants. They are most often given over a long period of time. Anticonvulsants are not given to people with brain metastases who have never had a seizure.
The type of anticonvulsant used depends on the type of seizures, how often they happen, how long they last, and other medicines being used. Some anticonvulsants interact with other medicines, which changes the levels of the drugs in the body.
Anticonvulsants are usually given orally (as a pill by mouth). Some may be given intravenously (through a needle into a vein). Anticonvulsants used for brain metastases include:
- phenytoin (Dilantin)
- carbamazepine (Tegretol)
- valproic acid (Depakene, Epival)
- oxcarbazepine (Trileptal)
- levetiracetam (Keppra)
- phenobarbital sodium
Side effects of anticonvulsants will depend mainly on the type and dose of the drug. Some side effects of these drugs are nausea and vomiting, skin problems (such as a rash), sleepiness, dizziness, problems with memory, problems with speech and liver damage.
Chemotherapy may be used to treat brain metastases, but it’s not a common treatment. It’s usually offered after all other treatments have been tried and is usually given along with other treatments, such as radiation therapy. Doctors also only use chemotherapy to treat brain metastases when they know that the primary cancer is likely to respond to chemotherapy. For example, brain metastases from testicular germ cell tumours are often treated with chemotherapy.
Chemotherapy uses drugs that circulate throughout the body and destroy cancer cells. The drugs, dose and schedule will vary for each person. The type of chemotherapy drug or combination of drugs used depends on where the cancer started and if the drugs can cross the blood-brain barrier. This barrier prevents toxic substances, like chemotherapy drugs, from entering the brain and spinal cord. Many chemotherapy drugs can’t cross the blood-brain barrier in large enough doses to treat brain metastases.
Side effects of chemotherapy will depend mainly on the type of drug, the dose and how it’s given. Common side effects of many chemotherapy drugs include low blood cell counts (called bone marrow suppression), nausea and vomiting, mouth problems and bowel problems.
Targeted therapy uses drugs that find and attach to specific substances (such as proteins) on the surface of or inside cancer cells. These substances help send signals that tell cells to grow or divide. The targeted therapy drugs block the substances to stop or slow the growth and spread of cancer cells.
Targeted therapy may be used to control the growth of brain metastases from some types of cancer. Some examples are:
- lapatinib (Tykerb) is given with a chemotherapy drug called capecitabine (Xeloda) for HER2-positive breast cancer
- dabrafenib (Tafinlar) is used for melanoma
- gefitinib (Iressa) is used for non–small cell lung cancer
Side effects of targeted therapy depend mainly on the type and dose of the drug. Common side effects of many targeted therapy drugs include flu-like symptoms and fatigue. Most side effects go away on their own or can be treated. Tell your healthcare team if you have these side effects or others you think might be from targeted therapy.
Find out more about targeted therapy.
Living with brain metastases
A diagnosis of brain metastases can often cause a great amount of fear and anxiety. A person with brain metastases may have concerns about the following.
Brain metastases often cause problems with the body’s functions and movements. The type of neurological problems that happen depend on the part of the brain affected. These problems may include:
- difficulty walking
- muscle weakness
- poor balance and coordination
- loss of memory and concentration
- changes in mood and behaviour
- problems with speech, swallowing or vision
Neurological problems can lead to stress and worry about losing your sense of self and your independence. Some treatments and supportive therapies can help manage and control neurological problems. Your healthcare team, including an occupational therapist and social worker, can also support you to cope with any neurological problems.
A diagnosis of advanced cancer can lead to questions about survival. There is no way of knowing exactly how long someone will live with brain metastases. It depends on many factors, including the type of cancer, the number of tumours in the brain and the treatments used. Survival with brain metastases is often measured in months, but some people can survive for several years. Some people may live much longer than expected, while others may die sooner than expected.
The best person to talk to about survival is the doctor. The doctor may be able to estimate survival based on what they know about a person and the type of cancer, but it’s not an exact science.
Find out more about living with advanced cancer.
The largest part of the brain, which contains different areas that control muscle function, thought, speech, emotions and learning.
The cerebrum is divided into 2 parts (called hemispheres) that are connected by a bridge of nerve fibres called the corpus callosum.
The part of the brain at the back of the skull (between the cerebrum and brain stem) that controls movement, balance, reflexes and other complex motor functions.
The stalk-like part of the brain that connects to the spinal cord. It controls basic body functions, such as breathing, hunger, heart rate, blood pressure and consciousness.
The 3 areas of the brain stem are the midbrain, pons and medulla oblongata.
The membranes that cover and protect the brain and spinal cord.
The meninges are made up of 3 layers. The outer layer is called the dura mater. The middle layer is called the arachnoid mater. The inner layer is called the pia mater. Together, the arachnoid mater and pia mater are called the leptomeninges.
Meninges is the plural of meninx.
Swelling caused by an abnormal buildup of fluid in the body.
Abnormal buildup of cerebrospinal fluid (CSF) in the ventricles (fluid-filled cavities) of the brain.
A sudden involuntary muscle movement or convulsion caused by uncontrolled electrical activity in the brain. Symptoms include muscle twitches, staring, tongue biting, urination, loss of consciousness and total body shaking.
A type of biopsy in which all of the tumour or abnormal tissue is removed, along with a margin of tissue around it, for examination under a microscope.
A procedure that uses a 3-dimensional scanning machine (ultrasound, CT scan or MRI) to find the precise location of a tumour and remove a sample for examination under a microscope.
Stereotactic biopsy is most often used on brain and breast tumours.
A protective network of blood vessels and cells that filters blood flowing to the brain.
The blood-brain barrier makes it hard for some substances (such as anti-cancer drugs) to enter the brain.
I’m extremely grateful to the Canadian Cancer Society for funding my research with an Innovation Grant.
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