A brain tumour is a collection, or mass, of abnormal cells in your brain. Your skull, which encloses your brain, is very rigid. Any growth inside such a restricted space can cause problems.
The brain is a soft mass of tissue that has three major parts, the cerebrum, cerebellum and the brain stem, all of which are effectively surrounded and protected by the bones of the skull; the brain is the tissue that controls people's voluntary and involuntary actions (that is, bodily functions, thoughts, and sensations). Any growth inside such a restricted space can cause problems.
Brain tumours can be cancerous (malignant) or noncancerous (benign). When benign or malignant tumours grow, they can cause the pressure inside your skull to increase. This can cause brain damage, and it can be life-threatening.
Brain tumours are categorized as primary or secondary. A primary brain tumour originates in your brain. Many primary brain tumours are benign. A secondary brain tumour, also known as a metastatic brain tumour, occurs when cancer cells spread to your brain from another organ, such as your lung or breast.
Types of brain tumours
There two types of brain tumours
Primary brain tumours originate in your brain. They can develop from your brain cells, the brain membranes, nerve cells or glands.
Primary tumours can be benign or cancerous. In adults, the most common types of brain tumours are gliomas and meningiomas.
Secondary brain tumours make up the majority of brain cancers. They start in one part of the body and spread, or metastasize, to the brain. The following can metastasize to the brain:
lung cancer
breast cancer
kidney cancer
skin cancer
Secondary brain tumours are always malignant. Benign tumours don’t spread from one part of your body to another.
Risk factors for a brain tumour
Risk factors for brain tumours include:
Family history
Only about 5 to 10 percent of all cancers are genetically inherited, or hereditary. It’s rare for a brain tumour to be genetically inherited. Talk to your doctor if several people in your family have been diagnosed with a brain tumour. Your doctor can recommend a genetic counselor for you.
Age
Risk for most types of brain tumours increases with age.
Race
Brain tumours in general are more common among Caucasians. However, African-American people are more likely to get meningiomas.
Chemical exposure
Being exposed to certain chemicals, such as those you might find in a work environment, can increase your risk for brain cancer.
Exposure to radiation
People who have been exposed to ionizing radiation have an increased risk of brain tumours. You can be exposed to ionizing radiation through high-radiation cancer therapies. You can also be exposed to radiation from nuclear fallout. The nuclear power plant incidents in Fukushima and Chernobyl are examples of how people can be exposed to ionizing radiation.
Symptoms of a brain tumour
Symptoms of brain tumours depend on the location and size of the tumour. Some tumours cause direct damage by invading brain tissue and some tumours cause pressure on the surrounding brain. You’ll have noticeable symptoms when a growing tumour is putting pressure on your brain tissue.
Headaches are a common symptom of a brain tumour. You may experience headaches that:
are worse in the morning when waking up
occur while you’re sleeping
are made worse by coughing, sneezing, or exercise
You may also experience:
vomiting
blurred vision or double vision
confusion
seizures (especially in adults)
weakness of a limb or part of the face
a change in mental functioning
Other common symptoms include:
clumsiness
memory loss
confusion
difficulty writing or reading
changes in the ability to hear, taste, or smell
decreased alertness, which may include drowsiness and loss of consciousness
difficulty swallowing
dizziness or vertigo
eye problems, such as drooping eyelids and unequal pupils
uncontrollable movements
hand tremors
loss of balance
loss of bladder or bowel control
numbness or tingling on one side of the body
trouble speaking or understanding what others are saying
changes in mood, personality, emotions, and behaviour
difficulty walking
muscle weakness in the face, arm, or leg
Diagnosis brain tumours
Diagnosis of a brain tumour begins with a physical exam and a look at your medical history.
The physical exam includes a very detailed neurological examination. Your doctor will conduct a test to see if your cranial nerves are intact. These are the nerves that originate in your brain.
Your doctor will look inside your eyes with an ophthalmoscope, which is an instrument that shines a light through your pupils and onto your retinas. This allows your doctor to check how your pupils react to light. It also allows your doctor to look directly into your eyes to see if there’s any swelling of the optic nerve. When pressure increases inside the skull, changes in the optic nerve can occur.
The doctor may also evaluate your:
Muscle strength
Coordination
Memory
Ability to do mathematical calculations
Your doctor may order more tests after they finish the physical exam. These could include:
CT scan of the head
CT scans are ways for your doctor get a more detailed scan of your body than they could with an X-ray machine. This can be done with or without contrast.
Contrast is achieved in a CT scan of the head by using a special dye that helps doctors see some structures, like blood vessels, more clearly.
MRI of the head
If you have an MRI of your head, a special dye can be used to help your doctor detect tumours. An MRI is different from a CT scan because it doesn’t use radiation, and it generally provides much more detailed pictures of the structures of the brain itself.
Angiography
This study uses a dye that’s injected into your artery, usually in the groin area. The dye travels to the arteries in your brain. It allows your doctor to see what the blood supply of the tumours looks like. This information is useful at the time of surgery.
Skull X-rays
Brain tumours can cause breaks or fractures in the bones of the skull, and specific X-rays can show if this has occurred. These X-rays can also pick up calcium deposits, which are sometimes contained within a tumour. Calcium deposits may be in your bloodstream if your cancer has moved to your bones.
Biopsy
A small piece of the tumour is obtained during a biopsy. A specialist called a neuropathologist will examine it. The biopsy will identify if the tumour cells are benign or malignant. It will also determine whether the cancer originated in your brain or another part of your body.
Treatment of brain tumours
The treatment of a brain tumour depends on:
The type of tumour
The size of the tumour
The location of the tumour
Your general health
The most common treatment for malignant brain tumours is surgery. The goal is to remove as much of the cancer as possible without causing damage to the healthy parts of the brain. While the location of some tumours allows for easy and safe removal, other tumours may be located in an area that limits how much of the tumour can be removed. Even partial removal of brain cancer can be beneficial.
Risks of brain surgery include infection and bleeding. Clinically dangerous benign tumours are also surgically removed. Metastatic brain tumours are treated according to guidelines for the type of original cancer.
Surgery can be combined with other treatments, such as radiation therapy and chemotherapy.
Physical therapy, occupational therapy, and speech therapy can help you to recover after neurosurgery.
Outlook
The outlook for a brain tumour will depend on:
The type of tumour
The size of the tumour
The location of the tumour
Your general health
Early treatment can prevent complications that can occur as a tumour grows and puts pressure on the skull and brain tissue. See your doctor if you’re worried about any symptoms you’re experiencing.
