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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
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