Treatment for primitive neuroectodermal tumour (PNET) | Cancer Research UK
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Treatment for primitive neuroectodermal tumour (PNET)

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This page is about treatment for the most common type of PNET brain tumour called medulloblastoma. There is information about

 

A quick guide to what's on this page

Treatment for PNET/ Medulloblastoma

The most common type of PNET is called medulloblastoma. These grow in the cerebellum (hindbrain). The main treatment is surgery to remove the whole tumour or as much of it as possible. If the tumour has made fluid build up in the brain (hydrocephalus) you may need to take steroid tablets until you have an operation. The surgeon may make a hole to allow the fluid to drain into another area of the brain (called a venticulostomy) or they may put a shunt in. This reduces the swelling and fluid collection. Reducing the fluid build up reduces the pressure in the skull and helps to control the symptoms caused by the tumour. 

After the surgery there is a risk that the tumour may come back or spread to other areas of the brain or spinal cord. So it is important to have radiotherapy to the brain and sometimes the whole of the spinal cord after surgery.

Treatment for children under 3

There are 3 main types of medulloblastoma. Those that occur in very young children tend to be a type called desmoplastic tumours. These tumours are very sensitive to treatment and can often be cured with chemotherapy on its own. The child has chemotherapy using a number of drugs given into a vein. They also have chemotherapy into the fluid around the spinal cord (intrathecal chemotherapy).

If the PNET comes back

For older children and adults, chemotherapy is mainly used to treat the tumour if it comes back after surgery and radiotherapy. PNET responds quite well to chemotherapy and doctors use a variety of different single drugs and combinations of drugs.

 

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Surgery for PNETs/ medulloblastoma

The most common type of PNET is medulloblastoma. These most often occur in the cerebellum at the back of the brain. The main treatment is surgery to remove the whole tumour or as much as possible. 

If the tumour has made fluid build up in the brain (hydrocephalus) you may need to take steroid tablets until you have an operation. The surgeon may make a hole to drain fluid into another area of the brain (known as a ventriculostomy operation) or they may put a tube called a shunt in. This reduces the swelling and fluid collection in your brain. 

Reducing the fluid build up reduces the pressure in your skull and helps to control the symptoms of your brain tumour. In up to 4 out of 10 patients (40%) the shunt needs to stay in place after surgery to stop further fluid build up.

About 1 in 4 people who have tumours in the cerebellum have particular symptoms after surgery. The symptoms are called posterior fossa syndrome and they can be very mild or more severe. The symptoms include difficulty talking (sometimes not being able to talk at all), difficulty swallowing, some difficulty with movement or walking, and emotional changes. 

These signs and symptoms of posterior fossa syndrome may develop from one day to a week after surgery. They usually improve slowly over a few weeks or months but they don't always go away completely. The cause of the symptoms is not known but researchers are trying to find out.

 

Radiotherapy for PNETs/ medulloblastoma

Primitive neuroectodermal tumours have a tendency to spread to other areas of the brain or spinal cord through the cerebrospinal fluid. In about 1 in 5 patients (20%) with a medulloblastoma it has spread to the spinal cord when they are diagnosed. In other people there is a risk that it will spread. So it is important to have radiotherapy to the brain and the whole of the spine after surgery.

 

Treatment for children under 3

If at all possible, specialists avoid using radiotherapy to the whole brain and spine on children younger than 3. Their young age makes them more likely to develop long term side effects. The doctor may suggest chemotherapy to keep your child's tumour under control until radiotherapy is likely to cause less damage. The exact combination of drugs used and the timing varies. 

In general your child is likely to have high dose chemotherapy with a number of drugs, as well as radiotherapy just to the area containing the tumour. In that way, the specialist may be able to avoid giving radiotherapy to the whole brain and spinal cord. Or radiotherapy may be delayed until your child is older. 

There are 3 main types of medulloblastoma.

  • Desmoplastic
  • Classic
  • Anaplastic

Those that occur in very young children tend to be a type called desmoplastic tumours. These tumours are very sensitive to treatment and can often be cured with chemotherapy on its own. The child has chemotherapy using a number of drugs given into a vein. They also have chemotherapy into the fluid around the spinal cord (intrathecal chemotherapy).

 

Chemotherapy for PNETs

Medulloblastoma responds well to chemotherapy and doctors use a variety of different single drugs and combinations. Drugs that are used include

Sometimes a combination of chemotherapy and radiotherapy may be used. 

 

More information 

If you would like more information about treatment go to our section about brain tumour treatment.

You can find information about the outlook (prognosis) for these tumours on the brain tumour statistics and outlook page

You are also welcome to contact the Cancer Research UK nurses on freephone 0808 800 4040. Lines are open from 9am to 5pm, Monday to Friday. 

You can contact one of the brain tumour organisations or look at our brain tumour reading list. If you want to find people to share experiences with online, you could use CancerChat, our online forum.

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Updated: 16 March 2016