Children’s Cancer and Leukaemia Group 2008 Factsheet Medulloblastoma and Primitive Neuroectodermal Tumour (PNET) This information sheet is designed to be used with the accompanying booklet Brain and Spinal Tumours in Children and Young People – A Parent’s Guide. You will find some references to the Guide in this factsheet. You may also find it helpful to read the CCLG/Cancerbackup booklet A Parent’s Guide to Children’s Cancers which provides more information about cancers in children, their diagnosis and treatment and the support services available. You may also want to discuss the information with a nurse or doctor involved in the treatment of your child. What are Medulloblastoma and PNET? Medulloblastoma and primitive neuroectodermal tumour (PNET) are malignant brain tumours which arise from nerve cells. They occur mainly in childhood (usually under the age of 10), and only occasionally in adults. There are approximately 80 cases diagnosed each year in the UK. There is no known cause for these tumours. Medulloblastoma develops in the cerebellum, the part of the brain at the back of the head (see diagram page 37). This area of the brain is responsible for balance and co-ordination. PNET looks the same as Medulloblastoma under the microscope but can develop in any area of the brain other than the cerebellum. Medulloblastoma is more common than PNET. Medulloblastoma and PNET can spread via the cerebrospinal fluid (CSF) to other parts of the central nervous system. Spread to other organs outside of the central nervous system is rare. These tumours may block the flow of CSF leading to a condition called hydrocephalus (see page 8) and so raise the pressure inside the skull (raised intracranial pressure). What are the symptoms of Medulloblastoma? • Poor balance and coordination caused by damage to the cerebellum. • Headache, nausea, vomiting, and tiredness due to hydrocephalus and raised intracranial pressure. • Sight problems: Squint which may be caused by hydrocephalus pressing on the nerves supplying the eye muscles. Papilloedema (swelling of the optic nerve) which is caused by raised intracranial pressure. This can be seen PAGE 1 OF 3 CCLG Factsheet Medulloblastoma and PNET June 2008 when a doctor looks at the back of the eye (the retina) with an ophthalmoscope (a special light used to look through the pupil to the back of the eye). What are the symptoms of PNET? These vary depending on the area of the brain in which the PNET has developed (see section on clinical signs and symptoms of brain tumours page 2). What is the treatment? The first step is usually to relieve the hydrocephalus, if present, and so reduce the raised intracranial pressure. This may be achieved by removal of the tumour or by insertion of a shunt (a drain) to divert the blocked fluid build up. The next step in treatment is to remove as much of the tumour as possible, without damaging the surrounding brain tissue. However complete removal is not always possible. Before the operation to remove the tumour, a magnetic resonance (MR) scan (see page 4) of the brain and spine is usually performed to check whether the tumour has spread to any other area of the nervous system. A second scan is performed just after the operation to find out how much of the tumour has been removed. to the whole brain and spine (this is called craniospinal radiotherapy). This will also include the whole CSF space which surrounds the brain and spinal cord. Craniospinal radiotherapy is one of the most complex techniques used in radiotherapy departments and requires a lot of preparation and planning time. Radiotherapy is given with the child lying face down wearing a custom‑made perspex head mask. These masks are essential to ensure the head remains perfectly still during treatment. Radiotherapy treatment will also involve an extra boost of treatment to the area from where the original tumour was removed (the cerebellum in the case of medulloblastoma). Chemotherapy Chemotherapy has not, in the past, been used routinely for all children. However, chemotherapy is now often used for younger children as part of a clinical trial. The choice of drugs and how and when they will be given will be discussed with you by your consultant and liaison nurse. As children under 3 years will not receive craniospinal radiotherapy as standard they are treated using a chemotherapy only approach, at least initially. It may then be necessary to give radiotherapy to the tumour site only in some cases. Radiotherapy It is rarely possible to remove every cell of the tumour. Surgery will be followed by further treatment. Post‑operative radiotherapy is usually the standard therapy for children over the age of three years but may be needed in younger children if chemotherapy is not successful. As cells from medulloblastomas or PNETs can spread via the CSF, it is essential that radiotherapy is given What is the outlook? The aim of treatment is cure and, in general, medulloblastoma and PNET respond to treatment. For medulloblastoma that has not spread to any other area of the brain or the spinal cord, and has been completely or nearly completely removed by the operation, the chance of cure is good. However, cure can never be guaranteed. PAGE 2 OF 3 CCLG Factsheet Medulloblastoma and PNET June 2008 Regrettably, for medulloblastomas that have spread, or for PNET, there is a lower chance of cure. If the tumour recurs it may grow back relatively early, i.e. within the first year or two but can sometimes grow back more than five years later. If the tumour comes back after treatment the chances of curing it are very small. support link for patients diagnosed with a brain tumour and their families. Tel: 0845 130 9733 Website www.braintumourtrust.co.uk How will my child be followed up? This will include regular clinic visits and regular brain scans. It is important that any problems or symptoms your child has in between these clinic visits should be reported as soon as they occur. How your child is feeling is the most important aspect of follow‑up and this is just as important as scans. Who has produced this information? This factsheet has been produced by the Children’s Cancer and Leukaemia Group. The factsheets and accompanying booklet Brain and Spinal Tumours in Children and Young People, A Parent’s Guide have been sponsored by a donation from the Samantha Dickson Brain Tumour Trust Children’s Cancer and Leukaemia Group (CCLG) An organisation for professionals treating children with cancer, including coordination of clinical trials. The CCLG provides a range of information for patients and families affected by childhood cancer. Tel: 0116 249 4460 Website www.cclg.org.uk Samantha Dickson Brain Tumour Trust The Samantha Dickson Brain Tumour Trust raises funds for research and offers a vital PAGE 3 OF 3 CCLG Factsheet Medulloblastoma and PNET June 2008