Medulloblastoma is a fast-growing, high-grade brain tumour. Like many tumour types, the exact cause of medulloblastoma is not known. However, scientists are making significant strides in understanding its biology.
Changes have been identified in genes and chromosomes (the cell’s DNA blueprints) that may play a role in the development of this tumour. There are also a few rare, genetic health syndromes that are associated with increased risk for developing this tumour. These include Gorlin syndrome and Turcot syndrome.
Different subtypes of medulloblastoma tumours have recently been identified and described using “molecular classification.” Each subtype has different characteristics and may:
- Be more likely to occur in a specific patient age range
- Have different pathological, genetic and molecular biology characteristics
- Have different clinical outcomes (some subtypes have a much better prognosis than others)
This classification was outlined in a manuscript produced as a result of a consensus conference held by experts in Boston, MA in 2010. The four main subtypes of medulloblastoma are:
- Shh (Sonic Hedgehog subgroup)
- Group 3 tumours
- Group 4 tumours
Research through the Pediatric Brain Cancer Impact Grant has shown that there are twelve subtypes of medulloblastoma.
Common symptoms include, but are not necessarily limited to:
- Behavioural or personality changes
- Double vision
- Headaches (which are worse first thing in the morning)
- Lack of coordination
- Lethargy or sleepiness
Treatment/Standard of Care
The management of medulloblastoma involves a multidisciplinary team:
- Surgery is the most important first-line treatment and involves removing as much of the tumour as possible.
- Sometimes the CSF pathways do not re-establish themselves after surgery and then a shunt may be necessary to treat the raised intracranial pressure (hydrocephalus).
- Chemotherapy is usually an important part of the treatment plan. In very young children aged 3 years or less, it is standard to treat children with medulloblastoma using chemotherapy alone as radiation therapy can be associated with significant long-term health problems (late effects).
- Radiation therapy is used for older children and involves treatment of the brain and spine followed by a “boost” of extra radiation therapy to the area where the tumour started in the posterior fossa.