Although not as common as leukemias and brain tumors, thyroid cancer is the third most common solid tumor cancer type in children (Solid tumor cancers are those that produce a tumor mass, rather than leukemias that produce cancerous cells that circulate in the bloodstream). Thyroid cancer is the most common cancer of hormone glands (endocrine) in children. Still, thyroid cancer represents only 1% to 1.5% of all pediatric cancers. Of all cases of thyroid cancer, about 5% occur in children and teens.
As in adults, a thyroid nodule (localized lump or mass) is a common symptom of thyroid cancer. Thyroid nodules that develop in children and adolescents are even more likely to be cancerous than thyroid masses in adults. In adults with thyroid nodules, only about 5% turn out to be cancer. In children and teens, that percentage increases to over 26%. All children or teens who develop a lump in the thyroid or neck should be evaluated by a physician in order to ensure early diagnosis and treatment if cancer is indeed present. The prognosis is usually excellent for children who have cancer that has not spread outside of the thyroid gland.
In adults, thyroid cancer is 2 to 3 times more common in women than in men, but this distinction is less relevant for children. Girls under age 15 are somewhat more likely than boys to develop thyroid cancer and have 1.5 times the risk of boys. In adolescents over 15 years old, girls are 3 times more likely to get thyroid cancer than boys.
As mentioned, a neck lump or mass is the most common symptom of thyroid cancer in children. The mass is typically not painful. Enlargement of the lymph nodes in the neck may also occur. Children with thyroid cancer are not as likely as adults to have symptoms that are sometimes associated with thyroid cancers like vocal cord paralysis, hoarseness, breathing problems, or problems with swallowing. Still, affected children can occasionally develop these types of symptoms.
Many children with thyroid cancer have a family history of the condition. Thyroid cancer can be associated with certain inherited syndromes, like the multiple endocrine neoplasia (MEN) syndromes. Up to 25% of a particular form of thyroid cancer, medullary thyroid cancer, are hereditary.
As with adults, surgery is the mainstay of treatment for thyroid cancer in children. Fortunately, the prognosis is usually very good for children with thyroid cancer. Depending upon the type of cancer and extent of spread, radioactive iodine treatments, chemotherapy, or radiation therapy may be given after surgery. Replacement thyroid hormone in pill form may be required for life after treatment.
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"Fact Sheet: Pediatric Thyroid Cancer." American Academy of Otolaryngology -- Head and Neck Surgery. Jan. 2012.
Gerber, Mark E., et al. "Pediatric Thyroid Cancer." Medscape. 5 Apr. 2011.