Cancer is caused by a gene mutation. In recent years, scientists have made great progress in understanding how certain changes in a person's DNA can cause cells of the body to become cancerous. DNA carries the instructions for nearly everything our cells do. We usually resemble our parents because they are the source of our DNA. However, DNA affects more than our outward appearance. It influences our risks for developing certain diseases, including some kinds of cancer. When children are born with mutated DNA inherited from their parents, the mutations are present in every cell of their bodies. That means the mutations can be detected by testing DNA of blood cells.

The great majority of cancers are not caused by inherited DNA mutations, but are the result of mutations acquired early in the child's lifetime. Every time a cell prepares to divide, it must copy its DNA. This process is not perfect, and errors sometimes occur. Luckily, cells have repair enzymes that "proofread" DNA. Some errors can still slip past, especially when the cells are growing rapidly. This kind of gene mutation can happen at any time in life. Acquired mutations start in one cell of the body and pass on to all the cells that spring from it. These acquired mutations are present only in the patient's cancerous cells and will not be passed on to his or her children. Although the causes of mutations responsible for certain adult cancers are known (for example, cancer-causing chemicals in cigarette smoke), the reasons for DNA changes that cause childhood cancers are not known. Some of these can occur in developing fetuses and are already present at birth.

While great strides in treatment and care have been made, about 11,000 children in the United States under the age of 15 will be diagnosed with cancer in 2009 - making it the leading cause of death from disease in children of that age group.

The types of cancers that occur in children vary greatly from those seen in adults. Leukemias, brain and other nervous system tumors, lymphomas, bone cancers, soft tissue sarcomas, kidney cancers, eye cancers, and adrenal gland cancers are the most common cancers of children, while skin, prostate, breast, lung, and colorectal cancers are most common in adults. The stage of growth and development is another important difference between adults and children. The immaturity of children's organ systems often has important effects on treatment.

Also, unlike many adult cancers, there are no avoidable risk factors such as smoking or exposure to hazardous chemicals in the workplace that influence your child's risk of developing cancer. Therefore, there is nothing that a parent or child can do to prevent the disease. If your child does develop cancer, it is important to realize that there is nothing you or your child could have done to cause it.

Childhood cancers can be treated with a combination of treatments - such as chemotherapy, surgery and radiation therapy - that are chosen based on the type and stage of cancer. Most forms of chemotherapy affect only growing cells, so fast-growing childhood cancers tend to respond well to these treatments, though there are exceptions.

Since the 1960s, the majority of children with cancer have been treated at specialized centers designed especially for them. About 94% of children with cancer in the United States are treated at a children's cancer center that is a member of the Children's Oncology Group. All of these centers are associated with a university and most with a children's hospital.

These centers will be able to offer your child the most up-to-date treatment through participation clinical trials or studies of promising new therapies. Because childhood cancers are uncommon, treatment outcomes are more successful when managed by a cancer center. Be sure your child is treated at a center that can offer him or her the option of a clinical trial.

References

American Cancer Society, (2004). A Cancer Source Book for Nurses Eigth Edition. Sudbury, MA: Jones and Bartlett Publishers.

American Cancer Society, (2007). Cancer Facts & Figures 2007. Atlanta, GA: American Cancer Society.

American Cancer Society, (2007). Detailed Guide: Cancer in Children. Retrieved December 23, 2007, from American Cancer Society Web site: http://www.cancer.org/docroot/CRI/CRI_2_3x.asp?dt=7

Children's Oncology Group, (2007). Cure Search. Retrieved December 23, 2007, from Children's Oncology Group Web site: http://www.childrensoncologygroup.org/

"Detailed Guide: Cancer in Children." Cancer Reference Information. 19 May 2009. American Cancer Society. 24 Jun 2009 <http://www.cancer.org/docroot/lrn/lrn_0.asp>.

Hewitt, M., Weiner, S., & Simone, J. (2003). Childhood Cancer Survivorship: Improving Care and Quality of Life. Washington, D.C.: The National Academies Press.