Diagnosis of Brain Tumour
The symptoms of brain cancer vary widely and depend on what part of the brain the tumour is pressing on. Sometimes, when a tumour develops slowly, the symptoms develop so gradually that they are scarcely noticed.
Symptoms of brain tumours
As a tumour grows inside the skull it presses on the surrounding brain tissues, creating pressure. In addition, benign and malignant tumours may cause the brain around them to swell.
A headache is often the first symptom. Most headaches are not due to brain tumours; however, you should ask your doctor about headaches, which are severe, persistent, or recurrent.
Other symptoms include:
- Nausea and vomiting
- Difficulty in speaking, or thinking of words (dysphasia)
- Disturbed vision, hearing, smell or taste
- Weakness or paralysis in part of the body
- Loss of balance
- General irritability, drowsiness or a change in personality
- Loss of memory
These symptoms may be caused by other conditions; however, they are warning signs. Each may mean a tumour (either malignant or benign) and should be checked by your doctor.
A brain tumour may also cause seizures (also known as fits or convulsions) by irritating the nerve cells in the brain. Seizures may simply be a loss of consciousness for a few seconds, or they may involve muscle spasms or abnormal movements for half a minute or more.
There are more than 160 different types of brain tumours, of which some 40 are classified as malignant. It is possible that each type of tumour has different causal factors, and its degree of severity or malignancy (the grade of tumour), its location within the brain, the size of surrounding tissue mass affected by the tumour, whether it is diffuse or defined, are just some of the factors to be considered when classifying and treating brain tumours.
How a brain tumour is diagnosed
Your doctor will take a detailed history of your symptoms and examine you thoroughly. If a brain tumour is suspected, you may be referred to a neurologist or neurosurgeon: doctors who specialise in diseases of the brain, spinal cord and related nerves.
The specialist will check how different parts of your brain are functioning. This may include checking your reflexes (for example, your knee-jerks), the strength in the muscles of your arms and legs, and your ability to feel pinpricks and to distinguish between hot and cold on your skin. You may be asked to do some mental exercises, such as some simple metal arithmetic.
The doctor will also probably look into your eyes, using an ophthalmoscope, to see the end of the optic nerve. This nerve connects the eye directly to the brain and it may bulge a little if a tumour is pressing on your brain, increasing the pressure inside your skull (the intra-cranial pressure).
Two main tests, CT scanning and Magnetic Resonance Imagining (MRI), are used to detect brain tumours and help the doctors to plan the most effective treatment for you. If your doctor thinks you have a secondary tumour which has come from a cancer elsewhere in your body, you will need to have other tests to find the primary tumour: for example, tests on your breasts or lungs.
CT scan (formerly called a CAT scan)
A CT scanner is shaped like a large doughnut. It moves around your head (without touching it) and takes a series of x-rays pictures from many angles. A computer than uses these pictures to build up detailed cross section pictures of your brain, a bit like pictures of slices from a loaf of bread. To make the detail clearer in the pictures, a dye may be injected into a vein, usually in your arm. This may make you feel hot all over for a brief moment.
During the scan you will be asked to lie with your head inside an opening in the scanner. The whole test may take up to half an hour to complete, and is completely painless. Most people are able to go home as soon as their scan is over.
Magnetic Resonance Imaging (MRI)
This test is similar to a CT scan, but it uses magnetism instead of x-rays to build up a series of very clear and detailed cross section pictures of your brain. Like a CT scan, MRI is completely harmless. You will be asked to lie very still on a couch inside a metal cylinder, which is open at both ends. The cylinder makes some people claustrophobic, but you can usually take someone into the room with you to keep you company. The scanning process is quite noisy, and earplugs are often needed.
Angiogram (also called Arteriogram)
This is used only rarely. Dye is injected into an artery and a series of x-rays is taken as the dye flows through the blood vessels of the brain. This will show up the position of the tumour and the blood vessels supplying it. As you will probably need either an anaesthetic or other from of sedation, you may need to stay in hospital overnight.
Source: Anti-Cancer Council of Victoria “Brain Cancer: A Guide for People with Cancer, Their Families and Friends”