Pediatric Thyroid Cancer Statistics

Statistics on Differentiated Pediatric Thyroid Cancer

  • Papillary and follicular thyroid cancer accounts for only approximately 1% of all pediatric cancers in the 5-9 year old age group and up to 7% of cancers in the 15-19 year old age group.
  • Only 1 in a million children younger than age 10 years will get thyroid cancer.
  • In children under age 10, thyroid cancer tends to affect boys and girls with about equal frequency, but thereafter it generally becomes more common in girls. The ratio of girls to boys with differentiated thyroid cancer reaches a peak of over 5 to 1 in the 15-to-20 year-old age group.
  • Medullary thyroid carcinoma (MTC) accounts for 5% to 10% of all thyroid cancers. In children and adolescents, it is a very rare disease, affecting less than one child per million per year.

Causes

As the National Cancer Institute notes, no one knows the exact causes of thyroid cancer. Doctors can seldom explain why one person gets this disease and another does not.

Research has shown that people with certain risk factors are more likely than others to develop thyroid cancer. The following risk factors are associated with an increased chance of developing pediatric thyroid cancer:

Pediatric Differentiated Thyroid Cancer

  • For differentiated thyroid cancer, a risk factor is exposure at a young age to ionizing radiation, whether from ingestion of radioactive iodines (iodine is the building block of thyroid hormones) or external radiation, as used to treat some childhood cancers. The main example of this was the increased rate of thyroid cancer identified in children following the 1986 Chernobyl nuclear power plant accident.
  • In general, the differentiated thyroid carcinomas are not diseases that are passed from one generation to the next. However, there are some hereditary forms of the disease, although the exact cause of the disease in these families is not yet known. Some genetic syndromes such as Gardner syndrome and the Carney complex can have papillary thyroid carcinoma as part of the spectrum of disease. Some follicular thyroid carcinomas can be associated with a mutation in the PTEN gene, which causes Cowden syndrome. Gene mutations (RET/PTC, BRAF, among others) that cause differentiated thyroid cancer have also been identified within tumor cells. These mutations are not in all cells of the body and therefore are not expected to be hereditary.

Pediatric Medullary Thyroid Cancer

  • In children and adolescents, medullary thyroid cancer is almost always the familial form, meaning that it is due to a specific mutation (defect) in the DNA of the cells of the body. This mutation occurs in a gene called the RET proto-oncogene.

Last updated: February 21, 2007