Your thyroid gland is a butterfly-shaped organ at the base of your neck right below your voice box (larynx). In some cases, as you age, abnormal growths or lumps form within your thyroid gland, called thyroid nodules.
Symptoms of Thyroid Nodules
Thyroid nodules are usually without symptoms. Many people don’t know they have a nodule in their thyroid until it’s found during testing for other reasons, such as during an ultrasound on the arteries in the neck.
Only 3 to 5 out of 100 thyroid nodules are cancerous.
In some cases, your physician may feel a nodule during a routine physical exam while examining your neck. “Only rarely does a thyroid nodule get large enough to block the throat and cause difficulty swallowing or breathing,” says Dr. Cryar.
In most cases, thyroid nodules do not affect the function of your thyroid.
Causes of Thyroid Nodules
The tendency to have thyroid nodules may run in families. A family history of thyroid nodules makes you more at risk of developing them. They are most common in middle-aged women.
“Thyroid nodules and cancer can be caused by radiation exposure,” says Dr. Cryar, “usually from radiation treatment to the head or neck for another cancer.”
Radiation exposure from a nuclear disaster, as in Chernobyl, is also a risk factor for developing thyroid nodules and thyroid cancer. Dr. Cryar predicts there will likely be an increase in thyroid cancers in Japan following the nuclear leaks in Fukushima, Japan, in spring 2011.
If your physician discovers you have thyroid nodules — either on a routine physical exam — or with a CT or MRI scan— you should have the nodules evaluated to rule out thyroid cancer. Although most thyroid nodules are benign, there’s always the possibility of malignancy, cautions Dr. Cryar.
Evaluating Thyroid Nodules: Fine Needle Aspiration
In years past, almost all thyroid nodules were removed by surgery to avoid missing the few that were cancerous. Because most nodules are not cancer, this meant that most of those operations were not necessary. “We want to avoid unnecessary operations to avoid potential vocal cord damage and other risks from surgery, so we’ve developed less invasive ways of evaluating nodules,” explains Dr. Cryar.
Fine needle aspiration (FNA) of the thyroid gland is currently by far the best procedure to determine if a thyroid nodule is benign or cancerous without resorting to surgery. It’s a simple, nearly pain-free procedure, requiring no restrictions afterward. In most cases, your endocrinologist will use ultrasound guidance to ensure accuracy.
FNA is performed in your endocrinologist’s office, often without anesthesia, as the burning sensation from the anesthesia may be more uncomfortable than the procedure itself, notes Dr. Cryar.
“We usually take four or five samples by inserting very thin needles into the thyroid nodule,” says Dr. Cryar. These small samples of thyroid tissue are sent for evaluation by a cytopathologist, an expert in interpreting tissue obtained by FNA.
Treatment of Thyroid Nodules
Treatment of thyroid nodules depends whether they’re benign or cancerous.
- Cancer or suspicious for cancer –Your endocrinologist will recommend removal of your thyroid. Only 3 to 5 out of 100 thyroid nodules are cancerous.
- Indeterminate – In some cases, the FNA sample cannot be clearly classified as cancer or benign. Depending on the microscopic appearance of the FNA, your endocrinologist may recommend more frequent ultrasound exams, a repeat FNA, partial removal of the thyroid or genetic testing of another FNA sample.
- Benign – More than 90 percent of thyroid nodules are noncancerous and surgery is not necessary.
Even if your thyroid nodule is benign, your endocrinologist will recommend follow-up monitoring.
“FNA is very accurate and a benign result is reassuring, but you still need repeat thyroid ultrasounds over the next few years to watch for any change in the nodule. Growth of a nodule is considered suspicious for cancer until proven otherwise, and if the nodule grows, we will repeat the FNA to be certain the nodule does not contain an undetected cancer,” explains Dr. Cryar.
“This process for evaluating and following thyroid nodules has allowed us to find and treat thyroid cancers aggressively,” Dr Cryar says, “while allowing the majority of patients with a nodule to avoid an unnecessary operation.”