What is Cancer?



Cancer is a non-contagious disease caused by the abnormal, uncontrolled growth of cells. Our bodies are constantly making new cells and normally cells grow and multiply in a systematic way. However, in someone with cancer, they behave abnormally and may grow into a tumour. These tumours can be benign (not cancerous) or malignant (cancerous). Cancer cells also have the ability to spread throughout the body – this is known as metastases.

Cause of Cancer in Children

For the majority of children with cancer, it is not possible to identify an exact cause or explanation for developing cancer. Fewer than 5% of childhood cancers are due to genetic conditions.

It is important to remember that nothing you or your child did caused the cancer to happen. Nothing you could have done, would have prevented the cancer occurring.

Common Childhood Cancers

Acute leukaemia (including lymphoblastic and myeloid types) are the most common, representing 35% of all childhood cancers

Other common cancers include:


  • Central nervous system tumours – 17%
  • Lymphomas or tumours of lymphatic tissue – 11%
  • Neuroblastoma and Neural Crest Tumours – 8%
  • Wilms’ Tumour – 7%
  • Rhabdomyosarcoma and Soft Tissue Sarcomas – 5%