The brain controls the senses (sight, smell, hearing, taste and touch), emotions, memory and learning. It also regulates the heart, the muscles, all organs, and blood flow. Childhood brain tumours are caused by a group of diseases that affect the normal growth of tissue in the skull. They can be benign (without cancer) or malignant (cancerous), but even benign tumours can be difficult to treat and life-threatening because they occur so closely to vital brain regions.

Brain tumours in children are usually diagnosed between the ages of three and eight, but can occur at any age. The disease is usually diagnosed quickly because the signs that vital functions have been disrupted also show up quickly. The disease and its treatment can be very different depending on where the tumour occurs and how far the cancer has spread, but more than half of the children treated are considered cured of the disease.

After leukemia, brain cancer is the most common childhood cancer. About 20 Alberta children under the age of 14 are diagnosed with brain cancer every year.

Risk factors

Researchers don’t know why some children develop brain cancer.  Some studies have suggested links between brain cancer and such factors as exposure to the flu or measles at childbirth or environmental factors such as exposure to pesticides, but those results are preliminary and need further research.  Although cell phone use, telephone wires and artificial sweeteners have all been linked in media reports to brain cancer, the evidence supporting those theories is weak.

Other factors that may increase the risk of developing childhood brain cancer include:

• Radiation treatment to the head for other cancers
• Other diseases such as neurofibromatosis (a genetic disorder that triggers the growth of tumours anywhere in the body)

Genetic link

A small number of cases appear to have a genetic link, but in most cases there is no family history of the disease.

Detection and diagnosis

Since the brain controls the body’s most important functions, the signs that something is wrong appear early.  The child can show a variety of symptoms:

• headache and vomiting (especially early in the morning, but in any regular pattern),
• seizures,
• blurred vision,
• impaired speech,
• mood or personality changes,
• coordination difficulties,
• weakness and
• increased head size.  Infants can show a bulging fontanel (the “soft spot” on a baby’s head).

CT and MRI scans are used to diagnose brain tumours, but it takes a biopsy to definitively determine if it is cancer. That means a surgeon removes a small sample of the tissue to look at under a microscope.  A biopsy can often be performed by making a small hole in the skull and removing the sample with a needle.

A spinal tap, which involves taking fluid from the spinal column with a needle, is sometimes needed to check for cancer cells.

Treatment

Treatment options for childhood brain cancer include surgery, chemotherapy and radiation therapy, sometimes in combination depending on the progression of the disease.

Surgery is used to remove as much of the brain tumour as possible and for some forms of brain cancer, such as low-grade astrocytomas, it may be all the treatment that’s required.  But usually treatment of childhood brain cancer requires a variety of treatment options.

Chemotherapy is the usual treatment for children under three years of age because radiation can affect growth and brain development.  In other children it is used in combination with surgery.  Cancer-killing drugs are injected into a blood vessel or muscle.

Radiation therapy, concentrated beams of high-energy X-rays, is sometimes used alone or in combination with chemotherapy.

Related Links:

National Comprehensive Cancer Network (U.S.)  guide to treatment decisions with links to other sites

  National (U.S.) Cancer Institute guide to childhood cancers



Factors affecting prognosis

The chance of recovery depends on the type of brain cancer, how far it has spread and the child’s general health and age.  About 60 per cent of the children treated for brain cancer are considered cured.

Childhood cancer can result in what’s called “late effects”, health problems caused by treatment that can show up months or even years later.  Because the brain is still developing in children, it can be especially true for brain cancer and can result in learning disabilities, stunted growth, hearing or vision loss and seizures.

For more information on late effects see:

  National (U.S.) Cancer Institute

  Child Cancer Net