Early Thyroid Removal May Prevent Hereditary Medullary Thyroid Cancer
Individuals who are destined to develop medullary thyroid cancer as a result of an inherited gene mutation may avoid cancer if their thyroid gland is surgically removed in childhood, according to a study published in the New England Journal of Medicine.
The thyroid is a gland located at the bottom of the throat. It is responsible for producing hormones that aid in metabolism. Certain people are at extremely high risk of developing a particular type of thyroid cancer as a result of an inherited gene mutation. Individuals with a mutation in the RET gene are almost certain to develop medullary thyroid cancer. RET mutations are the cause of multiple endocrine neoplasia (MEN) type 2A and 2B and familial medullary thyroid cancer. For individuals with a RET mutation, the only hope of avoiding cancer is surgery to remove the thyroid gland before cancer develops or before it spreads beyond the thyroid.
In order to determine whether early removal of the thyroid gland could prevent or cure thyroid cancer among young people with a RET mutation associated with MEN 2A, researchers at Duke University and Washington University followed 50 patients for at least five years after surgery. The patients were 19 years of age or younger at the time of their surgery. Five to 10 years after surgery, patients were evaluated by physical examination and by a blood test to detect elevated levels of calcitonin (high levels suggest medullary thyroid cancer).
At the time of the follow-up exam, 44 of the 50 patients (88%) had normal levels of calcitonin, suggesting that they were free of cancer. The six patients who had elevated levels of calcitonin were considered to have medullary thyroid cancer; all six of these patients were eight years of age or older at the time of their surgery. The six patients with cancer at the end of follow-up were also more likely to have had evidence of cancer in their lymph nodes at the time of surgery.
The researchers conclude that young people with a specific gene mutation who have preventive surgery to remove the thyroid have a good chance of remaining free of thyroid cancer for at least five years after surgery. Children appear to be more likely to remain free of cancer if they have their surgery at a younger age (before eight years) and if they have surgery before cancer has spread to their lymph nodes. Longer follow-up is required before the cancer-free patients can be declared cured.
Reference: Skinner MA, Moley JA, Dilley WG et al. Prophylactic thyroidectomy in multiple endocrine neoplasia type 2A. New England Journal of Medicine. 2005;353:1105-13.
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