Thyroid nodules are very common. These masses within the thyroid gland are composed of tissue and/or fluid and are estimated to be present in more than 50 percent of those aged 50 and older. Nodules can run in families, are more common in women, and increase in frequency with age.
Patients diagnosed with a thyroid nodule often ask if their nodule needs to be biopsied or surgically removed. Sometimes the answer is yes, but often the answer depends on a number of patient and nodule-related factors. Catherine Sinclair, MD, FRACS, head and neck surgeon at Mount Sinai West, explains why your nodule may, or may not, need special attention.
How do you know if you need a biopsy?
More than 95 percent of thyroid nodules are non-cancerous, although a family history of thyroid cancer in a first-degree relative or whole-body/neck/chest radiation exposure may increase the risk. Nodules have a low cancer risk, so whether to biopsy depends on the size and ultrasound appearance of the mass.
Over the past decade, many nodules smaller than one centimeter have been incidentally detected on imaging (CT, MRI) that was ordered for another reason. Often these nodules were inappropriately biopsied, and, if the biopsy was positive for thyroid cancer, overly extensive total thyroid surgery was performed. Recent data from Japan and the United States suggests that appropriately selected thyroid cancers can remain stable over time. Termed “microcarcinomas,” these cancers are less than one centimeter in size and may be adequately managed without surgery or with limited thyroid surgery.
How is risk measured?
In an effort to reduce “incidentally diagnosed” microcarcinomas, the American Thyroid Association (ATA) Guidelines for Thyroid Nodules and Differentiated Thyroid Cancer classifies nodules into risk categories for biopsy based on thyroid nodule size and ultrasound appearance. Those classified as high-risk nodules should be biopsied when more than one centimeter in size, whereas low-risk nodules—depending on their appearance on ultrasound—should not be biopsied until they are one and a half to two centimeters in size. Many thyroid surgeons perform their own ultrasounds and use the ATA risk classification system (along with any biopsy results) to determine who should have a biopsy, which nodules should be operated on, and which nodules can be safely observed.
What are the symptoms and treatment for thyroid nodules?
In addition to posing a cancer risk, nodules may also need to be removed if they grow very large (greater than four centimeters) and cause symptoms like difficulty swallowing, neck discomfort, hoarseness of the voice, and airway compression with shortness of breath. Frequently, a thyroid lobectomy—the removal of a portion of the thyroid gland—may be adequate treatment for a non-cancerous thyroid nodule as well as for small cancerous nodules that are less than four centimeters. However, patients should speak with their surgeon in detail beforehand about the many additional factors affecting surgery, such as the status of the other thyroid lobe, your age, and your personal preferences.
In summary, a thyroid nodule may require an operation if there is a high risk of the nodule being cancerous or if the non-cancerous nodule is large and causing symptoms.
Non-cancerous nodules that are asymptomatic should be observed with intermittent ultrasound follow-up when appropriate. If surgery is necessary, the least aggressive option that will effectively treat the nodule should be chosen.
Catherine Sinclair, MD, FRACS, is a head and neck surgeon at Mount Sinai West, at 425 West 59th Street on the 10th floor. She is a board certified and fellowship-trained surgeon at the Head and Neck Institute, and treats all stages of thyroid disease and parathyroid disease.