Pediatric Thyroid Cancer Update

Where  is the Thyroid Gland? What does it do?

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.

Fast Facts:

• Thyroid cancer is the third most common solid tumor malignancy and the most common endocrine malignancy in children. 

• Thyroid Cancer occurs four times more often in young girls than boys 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, and specifically pediatric thyroid cancers should perform surgery.

Types of Thyroid Cancer in Children

• Papillary: 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 but it  can spread to the lymph nodes via lymphatics in the neck and occasionally spreads to more distant sites if not diagnosed and treated early or properly.

• Follicular: 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 the cancer to spread to other parts of the body, making the disease more difficult to control in growing children.

Papillary and Follicular Thyroid Cancers are classified as well differentiated thyroid cancers.

• Medullary: 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 in children worldwide. Medullary thyroid carcinoma (MTC) in the pediatric population is usually associated with a specific inherited genetic conditions, such as multiple endocrine neoplasia type 2 (MEN2). Sporadic Medullary thyroid cancers are less common in children.

• Anaplastic: This is the fastest growing and most aggressive type thyroid cancers, with abnormal cells that grow and spread rapidly, especially locally in the neck. There is NO cure for anaplastic thyroid cancer and survival rates are generally less than a year from diagnosis date. This form of cancer has not been documented in children.

Symptoms: Symptoms of this disease vary. Your child may have a lump or nodule in the neck (similar to a goiter), persistent swollen lymph nodes, a tight or full feeling in the neck, trouble with breathing or swallowing, dry cough not associated with allergies or cold,  voice changes and hoarseness. Sometimes hormonal problems associated with thyroid disease are evident, such as mood swings, palpitations or weight gain. 

Diagnosis: If any of these symptoms occur, or you have a family history of thyroid disease, thyroid nodules, tumors, goiter or thyroid cancer ask your pediatrician to check your child's neck as part of his or her regular annual physical or health examinations. The evaluation should consist of a manual head and neck examination to determine if unusual lumps are present. 

A blood test may be ordered to determine how the thyroid is functioning. If a nodule or tumor is found or if your child develops a "goiter " (which is rare) an ultrasound or ultrasonography uses sound waves and a computer to create an image of the thyroid gland and neck contents such as lymph nodes to better evaluate the presence of abnormal growths. 

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 any 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 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. 

• Please note that 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 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, such as the bones, lungs or other endocrine organs 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 and prognosis for well differentiated thyroid cancers in children diagnosed and treated early tend to be excellent. The best outcomes are seen in teenage girls, papillary type thyroid cancer, and tumors localized to the thyroid gland.

PDF DOWNLOAD:  Diagnostic and Treatment Options for papillary, follicular and Hurthle Cell  thyroid carcinoma review by Cristian M. Slough MD and Gregory Randloph MD 

SOURCE:   American Academy of Otolaryngology, Head and Neck Surgery