The thyroid is a butterfly-shaped gland located at the base of the throat. It has two lobes joined in the middle by a strip of tissue (the isthmus). The thyroid secretes three main hormones: 1) Thyroxine, that contains iodine, needed for growth and metabolism; 2) Triiodothyronine, also contains iodine and similar in function to Thyroxine; and 3) Calcitonin, which decreases the concentration of calcium in the blood and increases calcium in the bones. All three of these hormones have an important role in your child’s growth.
Thyroid cancer is the third most common solid tumor malignancy and the most common endocrine malignancy in children. It occurs four times more often in females than males and has similar characteristics as adult thyroid cancer. Surgery is the preferred treatment for this cancer. Although the procedure is often uncomplicated, risks of thyroid surgery include vocal cord paralysis and hypocalcemia (low blood calcium). Consequently, an otolaryngologist-head and neck surgeon, one experienced with head and neck issues, should be consulted.
Types of thyroid cancer in children
This form of thyroid cancer occurs in cells that produce thyroid hormones containing iodine. This type, the most common form of thyroid cancer in children, grows very slowly. This form can spread to the lymph nodes via lymphatics in the neck and occasionally spreads to more distant sites.
This type of thyroid cancer also develops in cells that produce thyroid hormones containing iodine. The disease afflicts a slightly older age group and is less common in children. This type of thyroid cancer is more likely to spread to the neck via blood vessels, causing cancer to spread to other parts of the body, making the disease more difficult to control.
This rare form of thyroid cancer develops in cells that produce calcitonin, a hormone that does not contain iodine. This cancer tends to spread to other parts of the body and constitutes about 5-10 percent of all thyroid malignancies. Medullary thyroid carcinoma (MTC) in the pediatric population is usually associated with specific inherited genetic conditions, such as multiple endocrine neoplasia type 2 (MEN2)
This is the fastest growing of the thyroid cancers, with abnormal cells that grow and spread rapidly, especially locally in the neck. This form of cancer is not seen in children.
Symptoms of pediatric thyroid cancer
Symptoms of this disease vary. Your child may have a lump in the neck, persistently swollen lymph nodes, a tight or full feeling in the neck, trouble with breathing or swallowing, or hoarseness.
Diagnosis of pediatric thyroid cancer
If any of these symptoms occur, consult your child’s physician for an evaluation. The evaluation should consist of a head and neck examination to determine if unusual lumps are present. A blood test may be ordered to determine how the thyroid is functioning. Ultrasonography uses sound waves and a computer to create an image of the thyroid gland and neck contents such as lymph nodes. Other tests that may be warranted include a radioactive iodine scan, which provides information about the thyroid shape and function, identifying areas in the thyroid that do not absorb iodine in the normal way, or a fine needle biopsy of an abnormal lump in the thyroid or neck. Sometimes it is necessary to remove a part of the tumor or one of the lobes of the thyroid gland, known as a thyroid lobectomy, for analysis to help establish a diagnosis and plan for management.
Treatments for thyroid cancer
If the tumor is found to be malignant, then surgery is recommended. Surgery may consist of a lobectomy, subtotal thyroidectomy (removal of at least one lobe and up to the near-total removal of the thyroid gland), or a total thyroidectomy. In children with papillary or follicular thyroid cancer, total or near-total thyroidectomy is currently the standard of practice, as children typically have more extensive disease at presentation, have higher rates of spread, and it reduces the risk of recurrence. In children, there is an increased need for repeat surgery when less than a total thyroidectomy is performed. Lymph nodes in the neck may need to be removed as part of the treatment for thyroid cancer if there is suspicion of a spread of cancer to the lymph nodes.
Surgery may be followed by radioactive iodine therapy, to destroy cancer cells that are left after surgery. Thyroid hormone therapy may need to be administered throughout your child’s life to replace normal hormones and slow the growth of any residual cancer cells.
If cancer has spread to other parts of the body, chemotherapy (treatment by chemical substances or drugs) may be given. This therapy interferes with the cancer cell’s ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells and shrink tumors. Radiation treatment may also be required for treatment of some forms of thyroid cancer.
In general, treatment outcomes for this type of cancer in children tend to be excellent. The best outcomes are seen in teenage girls, papillary type cancer, and tumors localized to the thyroid gland.