When your child is diagnosed with cancer, it can feel overwhelming. This phase involves finding out if your child has cancer, and determining the type of cancer they have. Children’s cancer can be difficult to diagnose, as many symptoms are similar to those caused by less serious conditions, or injuries. This means that your child may need several tests and medical appointments before you receive confirmation that your child has cancer.

If your doctor thinks your child has a brain or other CNS tumour, your child may have the following tests:

  • medical history and physical exam, including a neurological exam to check the nervous system
  • blood tests
  • urine tests
  • medical imaging, such as:
    • X-ray
    • computed tomography (CT) scan
    • magnetic resonance imaging (MRI)
    • positron emission tomography (PET) scan
  • biopsy
  • lumbar puncture (spinal tap).

Our section, How is cancer diagnosed? explains these tests in more detail.



Doctors use staging to describe how much the cancer has grown. Some of the tests for a brain or other CNS tumour will also help to stage the tumour. Staging measures:

  • where the tumour is
  • how big it is
  • if it has spread to other parts of the body.

Your doctor will use this information to choose the best way to treat the tumour. Staging also gives your doctor an idea of how well these treatments are likely to work (prognosis).

Childhood brain and other CNS tumours have no standard staging system. Instead, doctors base the tumour staging on a range of factors. These include the tumour’s size and where it is. Doctors then classify tumours into different risk groups.