Grading can help your doctor understand how quickly a brain tumour might grow.

The grade of a brain tumour describes how abnormal the cells look under a microscope.

Brain tumours can be:

  • low-grade – not cancer, sometimes called benign tumours
  • high-grade – cancer, also called malignant tumours.

Benign brain tumour (non-cancerous)


Low-grade brain tumours usually grow slowly and may not cause symptoms for a long time. They can cause problems as they grow and press on nearby areas of the brain.

Some low-grade brain tumours do not come back after treatment but others do. These will need further treatment. Sometimes a low-grade brain tumour can change over time and become high-grade.


Malignant brain tumour (cancerous)


High-grade brain tumours grow faster than low-grade tumours. They cause problems by spreading into and damaging nearby areas of the brain. Some rare tumours may spread to other parts of the brain or the spinal cord. They very rarely spread to other parts of the body.

Your doctors may talk about the grade of a brain tumour using a number. A brain tumour may be from grade 1 to grade 4.


Grade 1


These tumours are low-grade and grow slowly. They are sometimes called benign tumours because they are unlikely to come back after treatment.


Grade 2


These tumours are also low-grade and usually grow slowly. Depending on the type of brain tumour, they may be more likely to:

  • come back after treatment
  • change over time and become high-grade.

Your doctor can explain more.


Grades 3 and 4


These tumours are high-grade and grow more quickly. They are also called malignant (cancerous) brain tumours.