Astrocytomas are the most common type of brain tumour within the group of brain tumours called gliomas. About one third of all brain tumours and brain cancers diagnosed in the UK are astrocytomas.

They grow from a type of cell in the brain called an astrocyte, which is the most abundant cell in the brain. Astrocytes support and protect the neurons (nerves) and help to pass messages between them. Astrocytes, therefore, are vital in processing information in the brain.

There are many different types of astrocytoma and they can affect both adults and children.

Types of astrocytoma

Brain tumours (or tumors as they are known internationally) are graded from 1 - 4, according to what they look like under the microscope and how they are likely to behave. This means how fast they grow and how likely they are to spread.

Astrocytomas can be any grade.

  • Grade 1 astrocytomas ('pilocytic astrocytomas') These are slow growing, relatively contained and unlikely to spread to other parts of the brain. They are also unlikely to return after being surgically removed. They tend to grow in the cerebellum, which controls balance. They can also occur in the optic pathways, which are involved in sight.
Diagram of main parts of the brain
  • Grade 2 astrocytoma ('diffuse astrocytoma') The most common grade 2 astrocytoma is called a 'diffuse astrocytoma'. Diffuse means it does not have well-defined edges, which can make it more difficult to remove completely.They are slow-growing, but can sometimes return, following treatment, as a grade 3 astrocytoma.
  • Grade 3 astrocytoma ('anaplastic astrocytoma') They are fast-growing and often referred to as 'malignant' or cancerous. They often recur following treatment in a more advanced form i.e. grade 4 astrocytoma.
  • Grade 4 astrocytoma ('glioblastoma') Grade 4 astrocytomas are usually called glioblastoma. You may hear them called glioblastoma multiforme, or GBM for short.

Other brain tumours, which don't have astrocytoma in their name, are also actually astrocytomas as they grow from astrocytes. For example, some types of DIPG (Diffuse Intrinsic Pontine Glioma).

How are astrocytomas treated?

The treatment for astrocytomas depends on the grade of the tumour, as well as its size and location:

Grades 1 & 2

Treatment in adults is normally surgery to remove as much of the tumour as safely possible. How much will depend on where it is in the brain. If completely removed, this is called 'total or complete resection'.

At this point, you may be told about, or may like to ask about, 'biomarker testing' and biobanking.

More treatment may not be needed, but you will be regularly monitored with MRI scans. This is called 'watch and wait', where no treatment is given, unless your tumour changes or grows, or your symptoms worsen.

If the tumour cannot be completely removed, the surgeon will remove as much as possible. This is known as 'debulking' or 'partial resection'. This is more likely the case with Grade 2 astrocytomas whose edges are less well defined.

You may also be given radiotherapy to kill off any tumour cells that could not be reached during surgery. Again, this is more likely to be needed with Grade 2 tumours.

Occasionally, chemotherapy may also be given.

For children, chemotherapy, rather than surgery, is often the first line of treatment. Doctors try to avoid giving radiotherapy to children under 3.

Grade 3

As these tumours are faster growing and more likely to spread, the usual course of treatment is surgery followed by radiotherapy and sometimes chemotherapy.

The course of radiotherapy may be over several weeks.

For chemotherapy, the drug temozolomide is often used. Alternatively, in adults, another chemotherapy drug, carmustine, may be put into a 'wafer' and put directly into the brain during surgery. The carmustine will be gradually released as the wafer dissolves over 2 -3 weeks.

Radiotherapy is very rarely used in children under 3 years.

Grade 4

Grade 4 astrocytomas are usually referred to by the term glioblastoma. You may sometimes hear them called glioblastoma multiforme, or GBM for short, though these terms are less used nowadays. (Please see the Glioblastoma page for more information).

What causes an astrocytoma?

There is nothing you could have done, or avoided doing, that would have prevented you from developing a brain tumour.

As with most brain tumours, the cause is not known. Research into possible causes is focussing around our genes.

Our genes control the way our cells grow and divide. Mutations (changes) in our genes can cause this process to go wrong, resulting in the cells growing uncontrollably and forming a tumour. These changes are often the result of a mistake being made when the cell copies its DNA before dividing.

Research is helping to identify which genes are involved and will hopefully lead to more personalised treatments.

What is the prognosis for astrocytomas?

Information about prognosis can be difficult to receive - some people do not want to know, whilst others do. There is no wrong or right answer as to whether or when to receive such information. If you would like information about prognosis, please see our Prognosis page.

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