Brain tumour grades

Your brain tumour will be given a grade, depending on how the tumour cells look under a microscope. The grade is a number from 1 to 4. The number tells how quickly the tumour might grow. A higher number means a faster-growing tumour. 

Sometimes a low-grade tumour can become a higher-grade tumour. How a tumour behaves will also depend on the type of tumour you have. 

• Grade 1 tumours are usually called low-grade or benign. Usually they grow slowly and do not spread to other parts of the brain.
• Grade 2 tumours also grow relatively slowly (low grade) but in time they may spread to other parts of the brain or become malignant.
• Grade 3 or 4 tumours are called high-grade or malignant. They grow more quickly and are more likely to spread into normal brain tissue. It is common for higher-grade tumours to return some time after treatment. This is known as a recurrence.

Tumours that arise from the layers covering the brain are also graded. These tumours are normally graded from 1 to 3. Most of these tumours are grade 1 and they are usually cured by surgery. 

Knowing the grade of the tumour helps your doctors to decide if you need more treatment and what the outlook (prognosis) is. Your doctor will explain the grade and type of your tumour to you and what this means for your treatment plan.