What causes cancer in children?

May 29, 2015

When a child develops cancer, everyone has the same question: Why? In most cases, there is no obvious explanation. Cells in the body sometimes make mistakes when copying themselves, and some of those mistakes can turn into cancer. A few rare types of childhood cancer — such as retinoblastoma, a cancer in the retina of the eye — run in families. In those cases, children may have inherited faulty genes from their parents. There’s also some evidence that children are more likely to develop cancer if their mothers were exposed to large amounts of radiation or harmful chemicals such as pesticides during pregnancy. But for the most part, childhood cancers seem to pick their targets at random. There’s no way to predict which child might develop cancer or to pinpoint the blame when it happens.

What types of cancer occur in children?

In 2007, about 10,400 children under the age of 15 were diagnosed with cancer. The most common form of cancer in children is leukemia, a type of cancer of the white blood cells. Tumors in the brain and elsewhere in the nervous system are a close second. In fact, leukemia, brain tumors, and other nervous system tumors combined account for more than half of all childhood cancers. Other types of cancer that can strike children include neuroblastoma (a childhood tumor involving primitive nerve cells that often starts in the abdomen), Wilm’s tumor (which forms on one or both kidneys), lymphoma (cancer of the lymph tissues), bone cancer, retinoblastoma, and rhabdomyosarcoma (a tumor that forms in muscle tissue).

What are the symptoms of childhood cancers?

Symptoms in children depend on the type and location of the cancer. Leukemia can cause pain in bones and joints, weakness, fever, bleeding, and weight loss. Children with brain tumors may have headaches, blurred or double vision, dizziness, nausea, and trouble with walking or basic motor control. Neuroblastomas can cause swelling in the belly, bone pain, fever, or diarrhea and affect eye or muscle movements; Wilm’s tumor and tumors in muscles may produce localized pain, swelling, and lumps. If your child has any unusual symptoms, your first stop should be your child’s doctor. Because childhood cancers are relatively rare, more likely than not the signs your child exhibits are due to something else. However, persistent unexplained symptoms or the sudden occurrence of new ones warrant a visit to the doctor to check things out.

How are childhood cancers treated?

Just like adults, children with cancer can be treated with chemotherapy, surgery, radiation, or some combination of the three. Newer immunotherapy treatments may be available through clinical trials. Of course, the particular treatment depends on the type of cancer. Chemotherapy is the main treatment for leukemia. If the leukemia comes back or doesn’t respond to treatment, blood stem cell or a bone marrow transplant can give the child a chance to make new, healthy blood cells and will sometimes cure the disease when chemotherapy and radiation have failed. Chemotherapy, surgery, and radiation can all be used in the treatment of brain tumors.

If possible, a child should be treated at a center that focuses on childhood cancers. These centers employ specialists who may have more experience with rarer cancers and children’s special needs. They afford the most up-to-date-treatment by offering promising new therapies and participation in clinical trials. Specialized centers also provide the kind of atmosphere, encouragement, and support that children and their families need. Social workers, psychologists, and education experts can be vital members of the team.

What are the chances for recovery?

Cancer recovery is measured by five-year survival rates, and these outcomes for childhood cancers have increased dramatically in the last few decades. In the early 1960s, 45 percent of children with cancer lived five years or longer; today, the figure is 77 percent. The majority of kids can now expect to recover from their disease and live full lives, though they may experience some long-term side effects due to the damage that treatments can cause to healthy cells.

The five-year survival rate for childhood leukemia is about 82 percent, and for childhood brain and nervous system tumors it stands at about 74 percent. The five-year prospects for kids with lymphoma are fairly good: 96 percent for Hodgkin and 86 percent for non-Hodgkin lymphoma. For Wilm’s tumor, the five-year survival rate is about 92 percent, and for neuroblastoma, about 70 percent.

But each case is different, and keep in mind that these are survival rates for children diagnosed and treated more than five years ago. Kids with more recent cases may benefit from improvements in treatment.

Side effects and long-term effects

Cancer treatments are incredibly tough on the body. Chemotherapy, radiation, and surgery often create short-term problems in adults and children. Children who go through these treatments are also at risk of additional late-appearing and long-term health problems. Some of the more common late effects of treatment (appearing a few months or years after treatment ends) can include growth problems, learning disabilities, fertility problems, heart problems, hearing and vision loss, and additional cancers.

According to a large, long-term study published in the New England Journal of Medicine, 62 percent of childhood cancer survivors had one or more chronic conditions as adults (versus 37 percent of their siblings). About 28 percent of survivors had a severe, disabling, or life-threatening condition. (Among their siblings, the rate was 5.2 percent.) A lot of the patients in the study received treatment as early as the 1970s, however, and many treatment protocols have changed since then.

To help doctors better identify and manage these long-term effects, the Children’s Oncology Group has published a comprehensive set of guidelines for follow-up care. Remember that each case is unique, and your child’s health team can help you understand the challenges you might face. With the right treatments and plenty of support, most kids have a long future ahead.

References

American Cancer Society. What are the most common types of childhood cancers? August 17, 2010.

American Cancer Society. How are childhood cancers treated? 2008.

National Cancer Institute. Childhood cancers: Questions and answers. August 17, 2010.

American Cancer Society. What are the risk factors and causes of childhood cancer? August 17, 2010.

Children’s Oncology Group: Long-Term Follow-Up Guidelines for Survivors of Childhood, Adolescent, and Young Adult Cancers

Adult Survivors of Childhood Cancer Are Prone to Chronic Health Conditions

Mayo Clinic: cancer Survivors: Managing the Late Effects of Cancer Treatment

National Institutes of Health. U.S. National Library of Medicine. Genetics Home Reference. Retinoblastoma.

American Cancer Society. What is neuroblastoma?

Biggs, J.C., Horowitz, M.M., Gale, R.P., et al. Bone marrow transplants may cure patients with acute leukemia never achieving remission with chemotherapy. Blood. 1992 80:1090-1093.

Orentas, R. Immunotherapy in pediatric oncology: into the 21st century. Immunology and Allergy Clinics of North America. 1999. Vol 19, Issue 2, p.309-326.

American Cancer Society. Bone Marrow or Peripheral Blood Stem Cell Transplantation. 2009.

Last Updated: March 11, 2015