Thyroid nodules are very common and can be felt on routine physical exams in about five to 10 percent of patients. These nodules can also be found on ultrasound of the thyroid in about 25 to 50 percent of patients.
A nodule is a solid or liquid-filled lump that forms within the thyroid. The risk of cancer in a thyroid nodule is low, and 95 percent of all thyroid nodules are benign. Some patients are at increased risk of thyroid cancer if they have had exposure to radiation in the past, have a family history of thyroid cancer or have very large or abnormal nodules.
Determining if a thyroid nodule is cancerous requires an evaluation by a physician familiar with thyroid nodules and thyroid cancer. Physical exam findings that suggest an increased risk of cancer include hard or fixed nodules, enlarged lymph nodes or hoarseness of the voice.
Patients that are at a high risk for cancer will receive a blood test, which can determine if the level of thyroid-stimulating hormone (TSH) is above or below normal. Nodules that appear above normal are making too much thyroid hormone. Following this test, a patient receives a radioiodine scan, which will demonstrate overactivity of the nodule with a normal or depressed activity of the remainder of the thyroid gland.
While most thyroid nodules do not fall into this category, it is an important determination to make for all thyroid nodules. Please see the section on Hyperthyroidism and Graves Disease for more information about overactive thyroid nodules.
An ultrasound is the primary imaging study to evaluate all thyroid nodules. One of our experienced radiologists, in cooperation with our oncologic neuroendocrinologists, can determine if there are certain characteristics on ultrasound that will require a core needle biopsy of the nodule to make a diagnosis. A biopsy can be performed during an office visit or with a separate visit to the radiologist, and it is a very safe procedure with minimal discomfort.
The results of the thyroid biopsy will determine the next step in the evaluation of the nodule:
- If the patient's nodule is benign, small and not causing compressive symptoms, the recommendation is usually to observe the nodule with repeat physical exams and ultrasound after a period of six to 12 months.
- If the patient's biopsy cannot definitively determine if the nodule is benign or malignant, the recommendation will be to either surgically remove the nodule or request patient follow up in the near future, including a physical exam and ultrasound.
- If the biopsy is cancerous, most patients are recommended to undergo surgery to remove the thyroid gland and any involved lymph nodes.
Most thyroid nodules are benign and do not require any further treatment once the physician confirms that no cancer is present. Removal of a thyroid nodule is indicated only for those with compressive symptoms, those with overproduction of hormones from the nodule, or those with nodules where there is a suspicion of cancer. Those patients in which removal of the nodule is indicated will meet with one of our endocrinology surgeons to discuss the operation in further detail. Please see the section on thyroid surgery for more information.