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Thyroid Nodules
 

What is the thyroid gland?

The thyroid gland is a butterfly-shaped endocrine gland that is normally located in the lower front of the neck that produces thyroid hormones which are secreted into the blood and then carried to every tissue in the body to help the body use energy, stay warm and keep the brain, heart, muscles and other organs working normally.

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What is a thyroid nodule?

Thyroid nodule refers to an abnormal growth of thyroid cells that form a lump within the thyroid gland. Although most thyroid nodules are benign (noncancerous), a small percentage of thyroid nodules are cancerous. In order to diagnose and treat thyroid cancer at the earliest stage, most thyroid nodules need some type of evaluation.

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What causes a thyroid nodule?

Fortunately, nine out of 10 nodules are benign (noncancerous). These include colloid nodules, follicular neoplasms and thyroid cysts. Autonomous nodules, which overproduce thyroid hormone, can occasionally lead to hyperthyroidism. We do not know what causes most noncancerous thyroid nodules to grow.

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Thyroid cancer is the most important cause of a thyroid nodule. Fortunately, cancer occurs in less than 10% of nodules.

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How is a thyroid nodule evaluated and diagnosed?

Most nodules are discovered during an examination of the neck for another reason. Once the nodule is discovered, your doctor will try to determine whether the rest of your thyroid is healthy or whether the entire thyroid gland has been affected by a more general condition such as hyperthyroidism or hypothyroidism. Your physician will feel the thyroid to see whether the entire gland is enlarged and whether a single or multiple nodules are present. The initial laboratory tests may include measurement of thyroid hormone (thyroxine, or T4) and thyroid-stimulating hormone (TSH) in your blood to determine whether your thyroid is functioning normally. Since it’s usually not possible to determine whether a thyroid nodule is cancerous by physical examination and blood tests alone, the evaluation of the thyroid nodules often includes specialized tests such as thyroid ultrasonography and fine-needle biopsy.

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What is a thyroid ultrasound?

A thyroid ultrasound, which uses high-frequency sound waves to obtain a picture of the thyroid, should be used to evaluate thyroid nodules. The test is very accurate and can determine if a nodule is solid or filled with fluid and its exact size. It is also used to look for features associated with thyroid cancer. It is very helpful in identifying nodules that are too small to feel during a physical exam. The ultrasound can be used to keep an eye on thyroid nodules to see if they are growing or shrinking. Thyroid ultrasound also is used to localize the nodule and assist the placement of the needle within the nodule during a fine needle biopsy. The ultrasound is a painless test which many doctors may be able to perform in their own office.

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What is a thyroid scan?

A thyroid scan uses a small amount of a radioactive substance, usually radioactive iodine, to obtain a picture of the thyroid gland. A scan is usually done in hyperthyroid patients who have nodules to determine if a nodule is causing the hyperthyroidism due to overactivity. In the past, this test was also done to determine which nodules were at higher risk for containing a thyroid cancer, but thyroid ultrasound and fine-needle biopsy have largely replaced thyroid scans for this purpose.

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How are thyroid nodules treated?

Thyroid nodules that are known or suspected to be thyroid cancer are typically first treated by thyroid surgery. An experienced thyroid surgeon should remove all thyroid nodules thought to contain thyroid cancer. In some cases, a small thyroid cancer (< 1 cm) may be able to be monitored without surgery. Benign thyroid nodules need to be watched periodically. This is done by annual neck examination and often thyroid ultrasound is used over time to make sure that a nodule does not enlarge or develop a worrisome appearance. When benign thyroid nodules cause symptoms, they may also need to be removed.

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Fine-Needle Aspiration

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What is a fine-needle aspiration biopsy of a thyroid nodule?

A fine-needle aspiration biopsy of a thyroid nodule is a simple and safe procedure to see if a nodule is benign or malignant. Typically performed in the doctor’s office, a local anesthetic may not even be necessary.

 

Sometimes, medications like blood thinners may need to be stopped for a few days before to the procedure. Otherwise, the biopsy does not usually require any other special preparation. Patients typically return home or to work after the biopsy.

 

For a fine-needle biopsy, your doctor will use a very thin needle to withdraw cells from the thyroid nodule.

 

How is a thyroid FNA performed?

A thyroid FNA is done lying flat. After the neck is cleaned, a local anesthetic may be applied to reduce pain. A very thin needle is put through the skin and into the thyroid nodule, often using an ultrasound to ensure the needle is in the nodule. The needle is removed after several seconds, and a new needle is used for additional samples. Ordinarily, several samples will be taken from different parts of the nodule to give your doctor the best chance of finding cancerous cells if they are present. The cells are then examined under a microscope by a pathologist.

 

What should you expect after the procedure?

Most patients typically feel well after a thyroid biopsy. Some people will have mild neck discomfort at the site of the biopsy following the procedure. Tylenol® and ice compresses can be used to relieve discomfort.

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Radiofrequency Ablation (RFA)

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What is Radiofrequency Ablation?

Using high-frequency sound waves, radiofrequency ablation cauterizes thyroid nodules and cysts. Performed under local anesthesia, RFA is relatively painless and does not require general anesthesia. Doctors use guided ultrasound to insert a thermal probe into the thyroid nodule. Through selective heating of the probe tip, the nodule is destroyed. The cauterized tissue is then broken down by the body.

 

How do I prepare for an RFA?

Radiofrequency ablation is done in your doctor’s office under sterile precautions. In most cases, medications will not affect the procedure – unless you take blood thinners. The procedure is not performed if you have a pacemaker, implants, are pregnant or on medication for blood thinning. Do not wear makeup, lipstick or any metal jewelry on the day of the procedure.

 

What should I expect during the procedure?

You will be able to breathe, swallow and talk normally during the procedure. Two grounding pads will be attached to your thighs to prevent skin burn. A pre-procedure Xanax may be offered if you feel anxious. The doctor and staff will ask you several times during the treatment how you are doing and whether you feel discomfort.

 

You will be covered with sterile cloths and your neck will be disinfected. Your head will be placed on a small cushion in a slightly overstretched position. The doctor will use a very thin needle to place a local anesthetic under the skin in the area surrounding the thyroid gland.

 

How RFA Works

Internally cooled electrodes with different active tip lengths are connected to a generator that creates an electric circuit. Approved by the Food and Drug Administration, these tools are designed specifically for a thyroid radiofrequency ablation.

 

The probe is inserted into the thyroid nodules and the generator creates a high frequency wave that it sends directly to the tip of the needle, which, in turn, heats a few millimeters of the nodule’s tissue and treats it point by point.

 

An alternating electric current creates frictional heat around the electrode to immediately damage the nodule tissue in significant amounts in areas very close to the electrode. Nodule tissue farther removed from the electrode is heated slowly. When temperatures reach 46°C, irreversible cellular damage on the nodule occurs and when temperatures are increased to 60-100°C, the nodule tissue immediately coagulates.

 

How long is the procedure?

You should set aside two hours on the day of treatment. Depending on the size of nodule to be treated, the procedure will take between fifteen minutes to one hour. Pre-procedural care and post-procedural monitoring takes additional time. When the procedure is complete, site may be cooled with ice packs if necessary.

 

Is RFA painful?

The procedure is so gentle that most people have little to no discomfort. The thyroid gland itself is not sensitive to pain and the skin and areas surrounding the thyroid gland are anesthetized. Only 2% to 3% of patients experience discomfort – usually in the form of a temporary burning sensation, similar to that of being anesthetized at the dentist. In the event of severe discomfort, the procedure will be interrupted and anesthetic will be injected again until there is no pain. Radiofrequency ablation does not cause any scarring to the neck and, in most cases, one puncture of the skin is sufficient to treat the entire thyroid gland.

 

What should I expect after the procedure?

You will stay in a recovery area at least 30 minutes after the procedure. You should be able to return to your regular daily activities immediately. However, you will need to limit certain activities for a day or two following the procedure: no lifting over 11 pounds; no strenuous physical activities; and no activities that involve holding your breath such as playing a wind instrument, inflating something, etc. No singing, shouting or over-stressing the voice. If you feel any abrupt change, you should notify your physician immediately.

 

Am I a candidate for RFA?

The Korean Society of Thyroid Radiology (KSThR) implemented the following guidelines in 2018 and recommend RFA for patients with: benign thyroid nodules that produce compressive symptoms or cause cosmetic concern; nodules that produce excess thyroid hormone, hot nodules or autonomous functioning thyroid nodules; thyroid cysts that produce excess thyroid hormone; rapidly growing benign nodules or cysts; visually disturbing nodules or cysts; high risk for anesthesia; or patients who do not want surgery.

 

Radiofrequency ablation is not performed during pregnancy or on patients with implanted pacemakers or defibrillators. Radiofrequency ablation is not recommended for patients with: thyroid cancer (also called follicular neoplasm) that is diagnosed through fine-needle aspiration or core- needle biopsy; or a nodule that meets U.S. criteria of cancer, despite results from a fine-needle aspiration or a core-needle biopsy.

 

Your physician will ensure your thyroid nodule is benign before proceeding with RFA. This is confirmed through at least two ultrasound-guided, fine-needle aspiration or core needle biopsies. In some cases, a single benign diagnosis may be sufficient.

 

Surgery is currently the standard treatment for primary thyroid cancer. However, radiofrequency ablation may be an alternative for patients with primary thyroid cancer who refuse surgery or who are unsuitable for surgery. For those patients who refuse surgery or who are at high surgical risk, RFA also can be performed for recurrent thyroid cancers in the thyroid gland area or lymph nodes located in the neck.

 

How effective Is RFA?

Clinical trials measured the rate of reduction, therapeutic success, changes in symptoms and cosmetic improvement of benign thyroid nodules.

 

For “cold” benign nodules (those that do not produce excess thyroid hormone), clinical trials have shown a mean reduction rate of 32.7% to 58.2% at one month and 50.7% to 84.8% at six months. In most patients, nodule-related symptoms and cosmetic problems also significantly improved or disappeared. In a long-term follow-up study, RFA was effective over a four-year period with the nodules consistently decreasing to 93.5%.

 

For “hot” benign thyroid nodules (those that do produce excess thyroid hormone), clinical trials have shown volume reduction rates of 52.6% to 70.7% at six months and improved or normalized thyroid function in most patients. In a multi-center study, hyperthyroidism caused by “hot” nodules improved in all patients and was completely normalized in 81.8% of patients. This led to the conclusion that RFA can be considered an alternative to thyroid surgery or radioactive iodine therapy.

 

How many treatments are necessary?

For most average-sized nodules, one treatment will sufficiently decrease the size of the nodules. When nodules are close to vocal cord nerves or are very large nodules, repeated procedures may be necessary.

 

Untreated areas of “hot” nodules may interfere with the improvement in thyroid function. In these instances, complete ablation is required. For this reason, more than one treatment session may be necessary to successfully treat “hot” nodules.

 

What are the side effects or complications?

In a multi-center study of 1,459 patients organized by the Korean Society of Thyroid Radiology, the overall complication rate following radiofrequency ablation was 3.3%. The major complication rate was 1.4%.

 

While uncommon, complications can include: temporary voice changes, such as hoarseness; slight bleeding that usually disappears on its own within one day; wound infections; in rare cases there may be vomiting, cough or seared skin at the puncture; and patients with “hot” thyroid nodules have the possibility of hypothyroidism after the procedure.

 

Although rare, a complication would require an inpatient hospital stay or follow-up treatment.

 

Is there any follow-up care?

Following RFA, your physician will monitor the treated nodules with ultrasound scans at three, six and twelve months.