Diagnosing a brain tumour

Sunday 1 April, 2018

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On this page: Physical examination | Blood tests | CT scan | MRI scan | Further tests | Grading tumours | Prognosis | Key points


Many people diagnosed with a brain or spinal cord tumour first go to see their GP because they are feeling unwell. Occasionally a brain tumour will be found during a scan for something unrelated, such as a head injury. Some people have sudden symptoms (such as loss of consciousness, severe headache or a seizure) and go straight to a hospital's emergency department.

The doctor will ask you about your symptoms and medical history, and will do a physical examination. You may be referred to have more tests and scans to confirm a diagnosis of a brain or spinal cord tumour.

Physical examination

Your doctor will assess your nervous system to check how different parts of your brain and body are working, including your speech, hearing, vision and movement. This is called a neurological examination and may cover:

  • checking your reflexes (e.g. knee jerks)
  • testing the strength in your limb muscles
  • walking, to show your balance and coordination
  • testing sensations (e.g. your ability to feel pinpricks)
  • brain exercises, such as simple arithmetic or memory tests.

The doctor may also test eye and pupil movements, and may look into your eyes using an instrument called an ophthalmoscope. This allows the doctor to see your optic nerve, which sends visual information from the eyes to the brain. Swelling of the optic nerve can be an early sign of raised pressure in the skull.

Blood tests

You are likely to have blood tests to check your overall health. Blood tests can also be used to check whether the tumour is producing unusual levels of hormones, which could indicate that the pituitary gland is affected.

CT scan

A CT (computerised tomography) scan is a procedure that uses x-rays to take many pictures of the inside of the body and then compiles them into detailed, cross-sectional pictures.

A contrast dye may be injected into a vein to help make the scan pictures clearer. It may make you feel hot all over and leave a bitter taste in your mouth. You may also feel the need to pass urine. These side effects usually ease within minutes.

The CT scanner is a large, doughnut-shaped machine. You will lie on a table that moves in and out of the scanner. It may take about 30 minutes to prepare for the scan, but the actual test is painless and takes about 10 minutes. You will be able to go home when the scan is complete.

The dye used in a CT or MRI scan usually contains iodine. If you have had an allergic reaction to iodine or dyes during a previous scan, tell your medical team beforehand. You should also let them know if you are diabetic, have kidney disease or are pregnant.

"My doctor thought I had depression but I insisted on a CT scan as I had persistent headaches, felt disorientated and couldn't think clearly. The scan showed that I had a brain tumour." – Richard

MRI scan

An MRI (magnetic resonance imaging) scan uses a powerful magnet and a computer to make cross-sectional pictures of your body. It may not be safe to have an MRI if you have a pacemaker or any other metallic object in your body. Some types of metal are MRI-compatible, however, so discuss this with your medical team.

For an MRI, you may be injected with a dye that highlights the organs in your body. You will then lie on an examination table inside a large metal tube that is open at both ends.

The test is painless, but the machine can be noisy and some people feel anxious or claustrophobic in the tube. If you think you may become distressed, mention it beforehand to your medical team. You may be given medicine to help you relax or you might be able to bring someone into the room with you for support. You will usually be offered headphones or earplugs. The MRI scan takes 30–90 minutes and you will be able to go home afterwards.

The pictures from an MRI scanner are generally more detailed than pictures from a CT scanner. Many people who first have a CT scan will also need to have an MRI.

Further tests

You may also have some of the tests below to estimate how quickly the tumour is growing (the grade, see below) and whether it has spread into nearby tissue. This information helps your doctor plan treatment.

MRS scan

An MRS (magnetic resonance spectroscopy) scan can be done at the same time as a standard MRI. It looks for changes in the chemical make-up of the brain.

MR tractography

This MR (magnetic resonance) scan helps show the message pathways (tracts) within the brain, e.g. the visual tracts. It can be useful in planning treatment for gliomas.

MR perfusion scan

This type of MR scan shows the amount of blood flowing to various parts of the brain. It can also be used to help identify the type of tumour.

SPET or SPECT scan

A SPET or SPECT (single photon emission computerised tomography) scan takes three-dimensional pictures showing blood flow in the brain. You will be injected with a small amount of radioactive fluid and then your body will be scanned with a special camera. Areas with higher blood flow, such as a tumour, will show up brighter on the scan.

PET scan

For a PET (positron emission tomography) scan, you will be injected with a small amount of radioactive solution. Cancer cells absorb the solution at a faster rate than normal cells do and show up brighter on the scan.

Lumbar puncture

Also called a spinal tap, a lumbar puncture uses a needle to collect a sample of cerebrospinal fluid from the spinal column. The fluid is checked for cancer cells in a laboratory.

Surgical biopsy

If scans show an abnormality that looks like a tumour, some or all of the tissue may be removed for examination under a microscope. This is called a biopsy. In some cases, the neurosurgeon makes a small opening in the skull and inserts a needle to take a sample. In other cases, a larger part of the skull has to be removed (craniotomy) to get to the tumour.

Genetic tests

Every kind of cancer, including brain cancer, changes the genes of the affected cells. These gene faults are not the same thing as genes passed through families. The fault is only in the structure of the tumour cells, not in the normal cells. The study of these gene changes is called cytogenetics or molecular genetics. A pathologist may run special tests on cells from the tumour to look for these gene changes. The results can help your doctors tailor the treatment for that particular tumour.

Grading tumours

The grade of a tumour describes how quickly it is growing and how it is likely to behave. A specialist doctor called a pathologist examines a sample of tumour tissue under a microscope and looks for several features to work out the grade.

Brain and spinal cord tumours are usually given a grade on a scale of 1 to 4 (often recorded in Roman numerals as I-IV).

Grades 1 and 2 are the slowest-growing tumours. They are considered low-grade and are sometimes called benign. Grades 3 and 4 are fast-growing tumours. They are considered high-grade and often called malignant.

With other types of cancer, doctors give the cancer a stage to describe the extent of the cancer in the body. Primary brain and spinal cord tumours are not staged in this way as most don't spread to other parts of the body.

Prognosis

Prognosis means the expected outcome of a disease. You may wish to discuss your prognosis and treatment options with your doctor, but it is not possible for anyone to predict the exact course of the disease. There are many factors that may affect your prognosis. These include the tumour type, location, grade and genetic makeup; your age, general health and family history; and how well the tumour responds to treatment.

Both low-grade and high-grade tumours can be life-threatening, but the prognosis may be better if the tumour is low-grade, or if the surgeon is able to remove the entire tumour.

Some brain or spinal cord tumours, particularly gliomas, can come back (recur) and may change to a higher grade (progress). In this case, treatments such as surgery, radiation therapy or chemotherapy may be used to control the growth of the tumour for as long as possible, relieve symptoms and maintain quality of life.

Key points

  • Many people diagnosed with a brain or spinal cord tumour have symptoms caused by the tumour, such as dizziness, headaches or difficulty walking.
  • You will probably have a number of tests to diagnose the disease.
  • A physical examination checks how different parts of your brain are working.
  • You may also need a blood test to check your overall health and hormone levels.
  • Imaging scans, such as CT and MRI, allow the doctor to see pictures of the inside of the brain. You may be injected with a dye before these scans to help make the pictures clearer.
  • Other scans assess the brain's chemical make-up, blood flow in the brain, and whether there are active cancer cells.
  • A biopsy removes a sample of tissue for examination under a microscope.
  • The tests and scans help doctors diagnose the type of brain or spinal cord tumour you have, as well as its grade. The grade indicates how quickly the tumour is growing.
  • Primary brain and spinal cord tumours are not given a stage because they rarely spread to other parts of the body.
  • Many people want to know the likely outcome of their disease (prognosis). You will need to discuss this with your doctor, as it depends on many factors.

Reviewed by: Dr Brindha Shivalingam, Neurosurgeon, Chris O'Brien Lifehouse, NSW; Conjoint A/Prof Andrew Cole, University of New South Wales, Senior Staff Specialist and Director, Cancer Rehabilitation Service, Greenwich Hospital Rehabilitation Service, and Chief Medical Officer, HammondCare, NSW; Laraine Cross, Senior Clinician, Social Work and Psychosocial Oncology Services, Calvary Mater Newcastle, NSW; Dr Anthony Dowling, Medical Oncologist, St Vincent's Hospital Melbourne, VIC; Kate Fernandez, 13 11 20 Consultant, Cancer Council SA; Ian Gelling, Consumer; Anne King, Cancer Nurse Coordinator Neuro-oncology, WA Cancer and Palliative Care Network, WA; Jodie Nixon, Team Leader Cancer Occupational Therapy, Princess Alexandra Hospital, Brisbane, QLD; Prof Tamara Ownsworth, School of Applied Psychology, Griffith University, QLD; Dr Claire Phillips, Radiation Oncologist, Breast and Neuro-oncology, Peter MacCallum Cancer Centre, VIC.

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