Pediatric cancers occur between birth and 14 years of age.  Cancers that affect children ages 15 to 19 are known as adolescent cancers.  Pediatric cancers are very rare and may differ from adult cancers in the way they grow and spread, how they are treated, and how they respond to treatment. The most common types of childhood cancer are leukemia, brain and spinal cord tumors, lymphoma, neuroblastoma, Wilms tumor (a type of kidney cancer), retinoblastoma, and cancers of the bone and soft tissue.