If you or a loved one has symptoms that could point to a brain tumour, it’s natural to want answers quickly. Rest assured that doctors have a range of well-established diagnostic tests to investigate your symptoms, reach a diagnosis promptly, and determine the best next steps.
Brain cancer is usually diagnosed through a combination of a neurological examination, imaging scans such as a CT or MRI, and, in many cases, a biopsy to confirm the tumour type. Some patients also have blood tests or a lumbar puncture as part of this process.
In some cases, a brain tumour is picked up unexpectedly, for example, during a scan for an unrelated injury, or during investigations for a seemingly separate issue such as persistent headaches or a routine eye test that flags changes at the back of the eye.
In this blog, we’ll look at when doctors suspect a brain tumour, the tests used to confirm a diagnosis and what typically happens once you have your results.
When might doctors suspect a brain tumour?
Doctors may suspect a brain tumour when a patient reports certain persistent or worsening symptoms, including:
- Headaches that are new, keep recurring, are worse in the morning or when lying down or don’t respond to usual painkillers
- Seizures (fits), including in someone with no previous history of epilepsy
- Nausea or vomiting, particularly if it comes on suddenly or with a change in position
- Vision changes, such as blurred vision, flashing lights, or loss of peripheral vision
- Drowsiness or confusion, including changes in memory, personality or behaviour
Your GP will ask about your symptoms, how long you’ve had them, and may carry out a brief neurological examination. This involves checking your reflexes, coordination, memory, vision and sensation for signs of impaired brain function.
If your symptoms suggest a possible brain tumour, current UK guidance recommends an urgent referral, with direct access to an MRI scan (or CT if MRI isn’t suitable) typically arranged within two weeks.
How do doctors diagnose a brain tumour?
Diagnosing a brain tumour is a step-by-step process. Most people start with their GP, who will assess symptoms and refer for imaging or to a specialist if needed; some are seen more urgently via A&E if symptoms come on suddenly.
If a scan shows something that needs further investigation, you’ll usually be referred to a specialist neuro-oncology centre. Here, a wider team, including neurologists, neurosurgeons and radiologists, will review your scans, may request further imaging, and, if appropriate, arrange a biopsy sample to confirm exactly what type of tumour is present.
This combination of clinical assessment, imaging and tissue analysis is what allows doctors to reach an accurate diagnosis.
Types of tests used to diagnose brain cancer
A number of different tests may be used, either on their own or together, to investigate a suspected brain tumour:
- Neurological examination: testing reflexes, coordination, memory, vision and sensation for signs linked to brain function
- Imaging scans: CT and MRI scans to provide detailed pictures of the structure of the brain, with PET scans sometimes used for additional detail
- Blood tests: used to assess general health and, in some rare cases, hormone or tumour marker levels
- Biopsy: removing a small tissue sample to confirm whether a tumour is present and identify its type and grade
- Lumbar puncture: analysing cerebrospinal fluid, used for certain tumour types
The tests you are offered will depend on your symptoms, your scan results and the type of tumour your doctors suspect.
When a CT scan may be recommended
A CT (Computed Tomography) scan uses X-rays to build detailed cross-sectional images of the brain. It’s often one of the first scans used in the diagnosis of brain cancer because it’s quick, widely available and effective at picking up many types of abnormality, including bleeding, swelling, or a mass that could be a tumour.
A CT scan may be recommended in an emergency if you need to be assessed quickly, or when an MRI isn’t suitable, for example, if you have a pacemaker or other implant that isn’t compatible with the strong magnets used in MRI.
CT scans are also useful for looking at bone close to a tumour, which can help with surgical planning.
Why is an MRI usually the next step?
An MRI (Magnetic Resonance Imaging) scan uses magnetism and radio waves, rather than radiation, to produce highly detailed images of soft tissue.
Because brain tissue is soft, MRI images are generally considered the key imaging test for diagnosing and assessing a brain tumour, offering far more detail than a CT scan about its size, exact location and likely behaviour.
MRI scans are usually done with a contrast dye, given through a small cannula in your arm, which helps highlight the tumour and surrounding blood vessels more clearly.
Are blood tests used to diagnose brain cancer?
Blood tests alone generally cannot diagnose a brain tumour. However, they still play a useful supporting role in the diagnostic process. Doctors may use blood tests to check your general health, including liver and kidney function and blood cell counts, particularly if surgery or a biopsy is being planned.
When are further tests needed?
If imaging strongly suggests a brain tumour, further tests are usually needed to confirm the diagnosis and gather more detail. This most often means a biopsy, which allows doctors to examine tumour tissue directly under a microscope.
A PET-CT scan may also be used in some cases to further characterise a tumour or to distinguish a recurrence from changes caused by previous treatment.
If there’s a possibility that a tumour in the brain has spread from cancer elsewhere in the body, a CT scan of the chest, abdomen or other areas may be arranged to check for a primary cancer.
Where certain tumour types carry a risk of spreading through the cerebrospinal fluid, a lumbar puncture may also be recommended.
What is a lumbar puncture, and when is it used?
A lumbar puncture, sometimes called a spinal tap, involves inserting a fine needle into the lower back, under local anaesthetic, to collect a small sample of cerebrospinal fluid, the fluid that surrounds the brain and spinal cord. You’ll usually be asked to lie on your side with your knees drawn up, and the sample is then sent to a laboratory for analysis.
This test isn’t needed for every brain tumour. It’s most often used where there’s a chance that tumour cells could have spread through the cerebrospinal fluid, which is more common with certain tumour types, such as medulloblastoma or central nervous system lymphoma.
Afterwards, you may be monitored for a short period, and some patients experience a mild headache or back discomfort, which usually settles within a few days.
A lumbar puncture isn’t suitable if pressure inside the skull is too high, so doctors will usually check this with a scan first.
What happens after you’ve been diagnosed with a brain tumour?
Once a brain tumour diagnosis is confirmed, your case will usually be discussed by a multidisciplinary team. This team typically includes a neurosurgeon, a clinical or neuro-oncologist, a radiologist, a pathologist, and a clinical nurse specialist, who often acts as your main point of contact throughout treatment.
Your tumour will be graded from 1 to 4, based on how the cells look under a microscope, following the World Health Organization’s (WHO’s) classification system.
- Grades 1 and 2 are generally slower growing.
- Grades 3 and 4 are considered high-grade and tend to grow more quickly.
This grading, together with the tumour’s location, type and genetic profile, helps your specialist team to recommend a personalised treatment plan, which may include surgery, radiotherapy, chemotherapy, or a combination of these.
What treatment options are offered for brain tumours?
Once your tumour has been graded and assessed, your specialist team will recommend a treatment plan based on its type, grade and location, alongside your general health. Surgery is often considered first, with the aim of removing as much of the tumour as safely possible, and it can also provide a tissue sample for further analysis if this hasn’t already been done via biopsy.
Radiotherapy, which uses targeted radiation to control or destroy tumour cells, may be used after surgery, or on its own if surgery isn’t suitable.
Chemotherapy, which uses drugs to target rapidly dividing cells, may also form part of your plan, either alongside radiotherapy or separately, depending on the tumour type.
For many patients, a combination of these approaches is recommended, and your team will talk you through which options are most relevant to your specific diagnosis.
Can proton beam therapy be an option?
For some patients, proton beam therapy (PBT) may be considered as part of a radiotherapy plan. PBT uses protons, rather than conventional X-rays, to target a tumour with a high degree of precision. Because protons deposit most of their energy directly at the tumour site rather than continuing beyond it, PBT can help reduce radiation exposure to nearby healthy brain tissue.
This can be particularly relevant for tumours located near critical structures, such as the brainstem, optic pathways or skull base, and for children and younger patients, where sparing developing brain tissue may help reduce the risk of long-term side effects.
Whether PBT is a suitable option depends on the type, size and location of the tumour, and should be discussed with your healthcare team during treatment planning.
Consultant in brain tumour oncology Dr Michael Kosmin explains how proton beam therapy can help patients with brain tumours and skull base tumours.
Getting the right diagnosis is the first step
A brain tumour diagnosis can understandably feel overwhelming. But there is an established diagnostic process in the UK designed to investigate symptoms promptly and determine what is causing them.
Suspected cancer referrals are treated as urgent, and aim for urgent scans within two weeks if there is a strong suspicion of brain cancer. If you are diagnosed with a malignant brain tumour, you will be supported by a specialist team to provide both clinical and emotional support.
If you or a loved one has been diagnosed with a brain tumour and would like to understand whether proton beam therapy could form part of your treatment options, Proton International London can provide guidance. We treat private patients diagnosed with a range of brain tumours at our central London clinic.
To seek a private second opinion, or to start the referral process, please contact us.
Frequently asked questions about brain cancer tests
What is the first test used to diagnose a brain tumour?
The first step is usually a neurological examination by a GP or specialist, checking things like reflexes, vision, coordination and memory. If a brain tumour is suspected, this is typically followed by an urgent imaging scan, most often an MRI, or a CT scan if MRI isn’t suitable or isn’t immediately available.
Can blood tests diagnose brain cancer?
Blood tests, on their own, can’t usually detect most types of brain tumour directly, but they’re still a useful part of the diagnostic process, helping to check general health before further tests or surgery, and, for a small number of tumour types, measuring hormone or marker levels that can further support a diagnosis.
What are brain metastases?
Brain metastases, also called secondary brain cancer, occur when cancer cells spread to the brain from a primary cancer elsewhere in the body, most commonly lung cancer, breast cancer or melanoma. This is different from a primary brain tumour, which starts in the brain itself. In adults, secondary brain tumours are actually more common than primary ones.
Should I seek a second opinion for treatment after being diagnosed with a brain tumour?
Yes, seeking a second opinion is a normal and reasonable part of cancer care, and you shouldn’t feel uncomfortable asking for one. You can request a second opinion through your current specialist or MDT, or via your GP, who can refer you to another specialist, whether on the NHS or privately. It’s worth checking with your current team whether waiting for a second opinion could affect the timing of your treatment.
