A thyroid nodule is a growth or lump in the thyroid gland.
A goiter is an enlarged thyroid gland. However, an enlarged thyroid gland (goiter) may contain one or more nodules. A nodule is a distinct area of the gland that appears to be different from the rest of the gland. Nodules are common. Worldwide, lack of iodine in the diet is a very common cause of nodules. They are commonly found in family members. If they are over 1cm in size they carry a 5-15% risk of malignancy (cancer). Because of the chance of a nodule being cancerous, all nodules should be fully evaluated by a thyroid specialist. If you have a family history of thyroid cancer, smaller nodules (<1 cm) may also need to be evaluated.
These growths may be fluid filled (cysts) or solid, or combination of both (complex nodule). They can be measured at 2mm and grow to well over 4 cm causing compressive symptoms. Some symptoms of large nodules include difficulty swallowing, voice change (hoarseness) and sensation of choking, neck discomfort, uncomfortable swallowing or difficulty breathing when lying on back, lump in throat, and even annoying tickle or cough. Unfortunately, nodules less then 2 cm do not have symptoms associated with them and they can go unnoticed for years.
Chances of developing nodules increases as you get older. It is estimated that about 50% of the population will develop a small, unnoticeable thyroid nodule at some time in their life. Most people are unaware that they have these growths in their thyroid. Less then 10% of the population will have a nodule that is large enough to be found by a physician feeling, or palpating, your thyroid. Don’t feel embarrassed to ask your doctor to feel your thyroid for nodules; it should be examined during a general physical examination. Most nodules, however, are found incidentally while having x-rays for other reasons (i.e. CT neck, CT chest, chest x-ray, carotid Doppler studies). Most physicians examining your neck may not feel a nodule till it is a significant size. A thyroidologist (doctor specializing in thyroid disorders) can typically feel 1 cm nodules.
In my recent research in 2007 in University Texas Health Science Center San Antonio, the cancer rate in nodules in the South Texas area was 19%, higher then the national average. The follow up study continues to show the cancer rate at 15%, still well above the national average. The higher rate in South Texas is believed to be due to introduction of Ultrasound examination of the thyroid with ability to find and diagnose smaller lesions that went unnoticed prior to 2006.
If you have a nodule, you should have it evaluated by a physician trained in the diagnosis and management of thyroid nodules. Clinical Thyroidologists are specialty-trained physicians that only care for thyroid conditions. Endocrinologists, internal medicine specialists, ENT (ear, nose and throat) specialists, are experienced in assessing nodules. The doctor will take a careful history for risk factors for thyroid disease (including radiation exposure and family history of thyroid disorders), do a physical examination and order blood tests to check the function of the gland. If the thyroid function is normal, the next step is an ultrasound-guided fine needle aspirate (FNA) of the nodule. If the thyroid function tests are abnormal, a thyroid scan may also be recommended to see if the nodule is overactive (a “hot” nodule) or inactive (a “cold” nodule). FNA under ultrasound-guidance (UGFNA) is performed using up to six samples from each nodule. The use of ultrasound to guide the needle into the nodule is the test of choice for accurate results.
Certain forms of radiation have been associated with increased risk of malignancy in a thyroid nodule. Radiation for throat cancer can increase risk of thyroid nodule development, thyroid cancer and thyroid failure. If you had radiation treatments to your head, neck, tonsils, or thymus, you may be at a slightly increased risk of thyroid cancer and should be evaluated by a specialist.
The treatment of a nodule depends upon its cause. If the fine needle aspirate from your thyroid nodule shows benign, non cancerous cells, then the nodule may just be watched to make sure that it does not grow larger. Growth is an indicator for another biopsy
If the second biopsy comes back indeterminate, then you may be advised to have it removed surgically. But conservative management may also be appropriate if there are no suspicious findings of lymph nodes in your neck exam on ultrasound. If the fine needle biopsy is suspicious for cancer, then surgical removal is recommended. If you are advised to have surgery, you will need a surgeon very experienced with thyroid gland surgery and who performs at least 50 thyroid surgeries a year.
If the nodule is cancerous, most often a good surgery provides cure. Surgery is the main way to remove the cancerous nodule. Before surgery an ultrasensitive ultrasound of the neck lymph nodes (LN mapping, seeprocedures) may reveal cancer spread to the nodes. An ultrasound guided FNA of the lymph node with Thyroglobulin washing can change the extent of surgery 40% of the time. This is best performed by a Thyroidologist carrying the ECNU certification who has been certified as expert in such procedures. The ECNU physician performs several of these procedures weekly and can provide the exact location (missed by CT and MRI) for your surgeon for complete removal of the malignant tissue.
Post-operatively, you will take levothyroxine thyroid hormone tablets to replace the hormones made by your removed thyroid and to suppress the cancer cells’ growth in any remaining micro-cancer thyroid tissue. You will be followed closely afterward, with blood tests, cancer marker Thyroglobin (TgAg/TgAb), and TSH testing. Those tests will help determine your need for radioactive iodine treatment (see thyroid cancer)
Benign nodules can be monitored for growth by rechecking an ultrasound in 6-12 months. Even when nodules are not cancerous, they need to be removed if causing symptoms or larger then 4cm because of the higher risk of malignancy.
If you think you have thyroid nodules, or have a family member with a thyroid condition, visit an endocrinologist who specializes in thyroid conditions for diagnosis and treatment.
Academy of Clinical Thyroidologists: www.thyroidologists.com
Thyroid Information: www.hormone.org
American Thyroid Association: www.thyroid.org