What to Know About Follicular Thyroid Cancer

Follicular thyroid cancer develops in follicles inside the thyroid gland. Signs and symptoms include a goiter (lump) in the neck, pain and swelling, or breathing difficulty.

Follicular thyroid cancer is one of the more common forms of thyroid cancer, and it’s thought to be linked to iodine deficiency.

This type of thyroid cancer is highly treatable. If you receive a diagnosis, your care team may recommend a combination of surgery, radiation, and medication.

Read on to learn more about follicular thyroid cancer.

What is follicular thyroid cancer?

Follicular thyroid cancer makes up an estimated 10% to 15% of all cases of thyroid cancer. Follicular tumors are usually highly treatable and curable .

The disease is thought to be linked to iodine deficiency . Research suggests that follicular thyroid cancer affects about 25% to 40% of people in areas where iodine deficiency is common. But since iodine deficiency is currently rarer in countries like the United States, the incidence of the condition has fallen to about 10%.

This type of thyroid cancer affects the follicles, which are round structures inside the thyroid gland. When abnormal cells grow in your follicles, they can disrupt thyroid hormone function, as well as cause symptoms like pain, swelling, and difficulty swallowing.

Symptoms of follicular thyroid cancer

The thyroid contains follicles that use iodine from blood to produce important thyroid hormones. These hormones help perform a number of bodily functions, including:

• metabolism
• heart rate
• blood pressure
• body temperature

When abnormal cells begin to grow in these follicles, symptoms may include:

• a lump ( goiter ) in the neck that typically grows quickly
• a swollen neck
• swollen lymph nodes
• pain in the neck, jaw, or ears
• difficulty swallowing
• difficulty breathing
• voice hoarseness
• a chronic cough

If you experience any of these symptoms, it’s a good idea to contact a doctor. Additionally, if you have difficulty breathing, seek emergency medical care.

Follicular thyroid cancer diagnosis

Diagnosing follicular thyroid cancer occurs on a case-by-case basis but may include :

• Biopsy: This involves removing a tissue sample from the thyroid to check for cancerous cells.
• Imaging tests: Your doctor may want to get a closer look at your thyroid using CT scans or X-rays.
• Blood tests: These can check for levels of thyroid hormones .

Screening tests have risks , so they’re only recommended when there’s evidence of physical symptoms like a lump.

Causes and risk factors

People with a history of radiation therapy administered to the head or neck (such as for tonsil issues) during infancy or childhood have a higher risk of developing cancer.

For these people, thyroid abnormalities may appear within 5 years post-radiation therapy and as much as 20 years later. Radiation exposure during childhood in general, such as due to nuclear fallout, is also associated with a higher risk of thyroid cancer, particularly in children.

Other risk factors for thyroid cancer include:

• a family history of thyroid disease or multiple endocrine neoplasia (MEN) syndrome
• a history of goiter
• being female
• being Asian

Treatment options

Treatment can vary based on the progression of the disease and may include:

• Surgery: This can be a thyroidectomy (full removal of the thyroid) or lobectomy (partial removal).
• Radioactive iodine ablation: This involves consuming radioactive iodine in pill or liquid form in order to destroy cancerous cells.
• Medication: A doctor may recommend thyrotropin-suppressing medication to regulate thyroid function.
• Chemotherapy: If the cancer has spread outside the thyroid to other tissues, a doctor may suggest chemotherapy.

Survival rate

The outlook for follicular thyroid cancer is generally very good. According to the American Cancer Society , the 5-year relative survival rate for follicular thyroid cancer is approximately:

• over 99.5% for localized lesions
• about 98% for regional cancer, meaning it has spread to surrounding areas
• about 67% for distant cancer, meaning it has spread further throughout the body

Overall, the 5-year survival rate for all stages is nearly 98%. This means that the vast majority of people with follicular thyroid cancer survive for at least 5 years beyond their diagnosis, which in most cases signifies that it’s effectively cured.

The bottom line

If you notice symptoms like a lump in your neck or swollen lymph nodes, visiting a healthcare professional for an assessment is recommended. While a goiter doesn’t always mean cancer, it typically points to a thyroid issue.

Follicular thyroid cancer is highly treatable with measures like surgery.