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Brain tumour grades

Brain tumours are graded 1 to 4 according to their behaviour, such as the speed at which they are growing, and how likely they are to spread into other areas of the brain. Grades 1 and 2 are considered low grade brain tumours, while grade 3 and grade 4 brain tumours are high grade.

Over time, some brain tumours’ behaviour can change and the tumour may become, or come back as, a higher grade tumour.

Each year in the UK, Over 12,000 people are diagnosed with a primary brain tumour every year. 53% are diagnosed with non-cancerous tumours and 47% with cancerous tumours.

Brain tumours are graded from 1 to 4 depending on how they are likely to behave. These grades were set out by the World Health Organisation (WHO).

On this page, we’ll discuss:

How are brain tumour grades diagnosed?

Confirming the diagnosis of the different grades of tumours is done, where possible, by analysing cells from the tumour, taken during a biopsy or during surgery. A neuropathologist examines the cells in the laboratory, looking for particular cell patterns that are characteristic of the different types and grade of brain tumours.

  • If you are not sure what your grading means, then make sure you talk to your doctor or clinical nurse specialist. Don’t be afraid to get in touch with them with these types of questions – they are there to support you!
  • You might want to consider asking for a second opinion about your tumour diagnosis. You should talk to your GP or consultant about this. In our experience dealing, healthcare professionals are very open to allowing second opinions, recognising the sensitive nature of the diagnosis.
  • Talk through the types of symptoms that you might experience, and how this might affect your day to day life. For example, driving or employment.

Why is a brain tumour’s grade important?

Accurate diagnosis is important as it allows your medical team to give you information about how the tumour could behave in the future, and also to recommend treatment options. This could include a clinical trial.

Sometimes confirming the grade can be difficult as some low grade and high grade tumours can look very similar.

Low grade tumours

Low grade brain tumours are:

  • slow growing
  • relatively contained with well-defined edges
  • unlikely to spread to other parts of the brain
  • have less chance of returning (if they can be completely removed).

Grade 1 and 2 tumours are low grade, slow growing, relatively contained and unlikely to spread to other parts of the brain. There is also less chance of them returning if they can be completely removed. They are sometimes still referred to as ‘benign brain tumours’.

The term ‘benign’ is less used nowadays as this can be misleading. These low grade brain tumours can still be serious.

This is because a ‘benign’ brain tumour can cause harm by pressing on and damaging nearby areas of the brain, due to the limited space capacity of the skull. They can also block the flow of the cerebrospinal fluid (CSF) that nourishes and protects the brain, causing a build-up of pressure on the brain.

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High grade tumours

High grade brain tumours are:

  • fast growing
  • can be referred to as ‘malignant’ or ‘cancerous’ growths
  • more likely to spread to other parts of the brain
  • may come back, even if intensively treated.

Grade 3 and grade 4 brain tumours are high grade, fast growing and can be referred to as ‘malignant’ or ‘cancerous’ growths.

They are more likely to spread to other parts of the brain (and, rarely, the spinal cord) and may come back, even if intensively treated. They cannot usually be treated by surgery alone, but often require other treatments, such as radiotherapy and/or chemotherapy.

‘Mixed grade’ tumours

Some tumours contain a mixture of cells with different grades. The tumour is graded according to the highest grade of cell it contains, even if the majority of it is low grade.

If you have further questions, need to clarify any of the information on this page, or want to find out more about research and clinical trials, please contact our team:
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