Benign or Malignant? Screening for Thyroid Cancer

Thyroid polyps vs. thyroid cancer

Thyroid cancer statistics

In 2022, the American Cancer Society reported about 43,800 new cases of thyroid cancer (11,860 in men and 31,940 in women), resulting in about 2,230 deaths from thyroid cancer (1,070 men and 1,160 women).

Thyroid cancer had been the most rapidly increasing cancer in the United States — until recently. More sensitive diagnostic procedures, like CT and MRI scans, account for much of this rise. These procedures are able to detect incidental small thyroid nodules that might not have been detectable in the past.

It’s shaped like a butterfly

Located near the larynx and in front of the trachea, the thyroid is a small butterfly-shaped gland. The thyroid secretes two hormones which affect heart rate, body temperature, and many body processes that regulate metabolism. When the thyroid is not functioning correctly, or is secreting too few or too many hormones, it can cause various abnormalities such as lumps, nodules and edema in the neck.

Thyroid nodules

A thyroid nodule is a solid, fluid filled lump caused by abnormal cells found on the thyroid gland. A patient may notice a lump in their neck while looking in the mirror or buttoning up their shirt. Many times, there are no symptoms except for this slight change in appearance. The patient may not even notice it until someone else brings it to their attention. Rarely does a thyroid nodule cause pain, but if the nodule is too close to the windpipe, it can occasionally cause hoarseness or a tickle in the throat.

90% of thyroid nodules are benign. A small percentage of these nodules do contain cancer-causing cells, however, and most thyroid nodules need to be checked out by a healthcare professional. If aggressive thyroid nodules are left untreated, they will grow over time, metastasize (most often to the lymph nodes and lungs), and can ultimately result in death.

Types of thyroid cancer

There are three types of thyroid cancer: papillary thyroid cancer, follicular thyroid cancer, and medullary thyroid cancer.

Most thyroid cancers are papillary in origin, i.e. small and localized. Patients with these small localized papillary thyroid cancers have a 99% survival rate at 20 years. Papillary thyroid cancer can be caused by radiation therapy. These types of thyroid cancers are treated aggressively.

Follicular thyroid cancer is the second most common type of thyroid cancer, making up about 10-15% of all thyroid cancers. It’s considered a well-differentiated cancer, similar to papillary thyroid cancer, but tends to be more malignant. Follicular thyroid cancer is often seen in an older population.

Medullary thyroid cancer, also known as medullary thyroid carcinoma, is a rare type of thyroid cancer which begins in thyroid cells called C cells, which produce the hormone calcitonin. About one-third of patients with medullary thyroid cancer have a family history of thyroid cancer, but many individuals with this form may not know they’ve inherited cancerous genetic traits.

Typically, medullary thyroid cancer starts within the thyroid as growth or nodule, and is most commonly diagnosed as a lump in the neck.

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Screening for thyroid cancer

Individuals who notice lumps or swelling in their neck or throat should seek healthcare assistance. Palpable thyroid nodules are common, occurring in approximately 5% of U.S. adults aged 50 years and older when screened by palpation.

Although the U.S. Preventive Services Task Force (USPSTF) recommends against screening in the general asymptomatic adult population, several factors substantially increase the risk for thyroid cancer. These include a history of radiation exposure to the head and neck as a child, exposure to radioactive fallout, family history of thyroid cancer in a first-degree relative, and certain genetic conditions. (Familial medullary thyroid cancer or multiple endocrine neoplasia syndrome (type 2A or 2B) are some examples.)

Other thyroid cancers are often found on a routine checkup. Imaging tests such as ultrasounds and CT scans are also able to diagnose thyroid cancers early. Blood tests measuring for thyroid-stimulating hormone (TSH or thyrotropin), thyroglobulin, calcitonin or other compounds can find changes in the thyroid, though they are not recommended as a screening technique unless there is a family history of thyroid cancer.

Medullary thyroid cancer has a clear genetic link and runs in families. For those with a family history of this kind of cancer, experts recommend genetic testing for all family members.

A biopsy guided by ultrasound imaging is another method used to diagnose thyroid cancer. The technician inserts a fine needle into the thyroid to aspirate suspicious tissue. Healthcare professionals then send the sample to the lab to test for abnormal cell growth.

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When to worry

Healthcare professionals should examine any abnormality, swelling, throat hoarseness, and/or lump in the neck as soon as it is detected. Patients should get lumps checked, especially if swelling continues. When necessary, they should seek a second opinion.