Thyroid Cancer: How common is it?

Odds are, the lump is a thyroid nodule, a benign growth or fluid-filled cyst. These are very common, and many of us will have at least one by the time we reach the age of 60. More than 95% of these nodules are benign and usually don't need treatment unless they are large and cause issues with the voice or swallowing ability.

It's also possible that the lump in your neck is thyroid cancer, the 12th most common cancer in the US. The American Cancer Society's most recent (2023) estimates for thyroid cancer in the United States are 43,720 new cases of thyroid cancer per year, and thyroid cancer accounts for about 2,120 deaths.

It's important to understand that most thyroid cancers are highly treatable. and many can be completely cured since fast growing thyroid cancers are extremely rare. As with any type of cancer, early detection is the key to a good prognosis.

About Your Thyroid

The thyroid is a butterfly-shaped gland located at the base of the neck. Its job is to produce hormones that control your metabolism and vital body functions. Thyroid hormones help regulate:

• Breathing
• Body temperature
• Body weight
• Cholesterol levels
• Heart rate
• Menstrual periods
• Muscle strength
• Nervous system function

Symptoms of Thyroid Cancer

The most common symptoms of thyroid cancer are:

• A lump or swelling on the side of the neck
• Difficulty breathing
• Difficulty swallowing
• Voice changes such as hoarseness
• Feeling of a "tickle" in the throat
• A constant cough
• Pain in the neck, jaw, or ear
• Sore throat
• Thyroid cancer may also affect hormone production, causing symptoms such as flushing or diarrhea.

Diagnosing Thyroid Cancer

The first step to diagnosis is a physical exam where your doctor will palpate your neck looking for abnormalities. If a lump is found, your doctor may order an ultrasound and blood tests to check your levels of thyroid hormone and look for anti-thyroid antibodies in the blood to rule out or diagnose other thyroid conditions. Ultrasound imaging with a radioactive tracer may be ordered to help determine whether a nodule is cancerous. Your doctor may also order a CT scan of your neck. You may also be scheduled for a fine-needle aspiration biopsy to confirm the diagnosis and identify the type of thyroid cancer. If you are experiencing voice changes, your doctor will check your larynx with a device called a laryngoscope to evaluate the movement of your vocal cords.

Types of Thyroid Cancer

The thyroid gland is made up of two types of cells, which secrete different hormones. Follicular cells produce the hormones thyroxine and triiodothyronine. C-cells produce the hormone calcitonin. Some types of thyroid cancer originate in follicular cells while others start in the C-cells:

• Papillary thyroid cancer, the most common type, is slow-growing and develops from follicular cells. If left untreated, this cancer often spreads to lymph nodes.
• Follicular thyroid cancer, which develops from follicular cells, is a slow-growing tumor that rarely spreads to lymph nodes.
• Hurthle cell cancer originates in a particular type of follicular cell called a Hurthle cell and is more likely to spread to lymph nodes.
• Medullary thyroid cancer, or MTC, develops in the C-cells and is sometimes related to a genetic syndrome called multiple endocrine neoplasia type 2 (MEN2).
• Anaplastic thyroid cancer which accounts for only 1% of thyroid tumors, is fast-growing and more challenging to treat successfully than other thyroid cancers. It often arises in existing thyroid cancers such as papillary or follicular thyroid cancer.

Follicular thyroid cancer and papillary thyroid cancers, the most common thyroid malignancies, make up roughly 95% of all thyroid cancers. Both types are often curable when diagnosed early.

Thyroid Cancer Risk Factors

• Gender. Women are three times more likely to be diagnosed with thyroid cancer than men.
• Race. Thyroid cancer can affect people of any ethnic background, but Caucasian and Asian people have a higher risk than Black people.
• History of goiter (enlarged thyroid).
• Family history of thyroid disease or thyroid cancer.
• Genetics. Certain rare thyroid cancers, including medullary thyroid cancer (MTC) are associated with genetics. Additional genetic risk factors include MEN2 syndrome (see above) and a family history of precancerous colon polyps. Radiation Exposure. This could be from past radiation therapy, radioactive iodine, or other sources. Routine dental X-rays, chest X-rays and mammograms are not associated with an elevated risk of thyroid cancer.
• Diet low in iodine, which is needed for normal thyroid function.

Treating Thyroid Cancer

Surgery is the first line of defense for almost all thyroid cancers, as well as for benign thyroid nodules that require removal. Treatment may call for removing part of the thyroid (lobectomy) or the entire gland (thyroidectomy). If the entire thyroid is removed, thyroid hormone pills will have to be taken for the rest of life. In the case of a lobectomy, the remaining thyroid tissue may be able to increase hormone production to compensate for the tissue that was removed. Other possible treatments include:

• Radioactive Iodine Therapy is used to treat hyperthyroidism as well as some thyroid cancers. It targets thyroid cells so there is little exposure to the rest of the body's cells.
• Thyroid Hormone Therapy involves taking a higher-than-normal dose of thyroid hormone after a thyroidectomy to lower levels of TSH, a pituitary hormone that regulates thyroid function and stimulates the growth of thyroid and thyroid cancer cells.
• Chemotherapy is sometimes used in combination with external beam radiation therapy to treat anaplastic thyroid cancer.
• Targeted Drug Therapy with kinase inhibitors may be prescribed to treat certain thyroid cancers. Kinases are proteins that spur cell growth and blocking them can inhibit the growth of cancer cells.

Learn more about thyroid cancer and treatments.

If you are experiencing symptoms of thyroid cancer, make an appointment with your doctor now. With early diagnosis and treatment, the prognosis for this type of cancer is usually very good. If you need help finding a doctor, click here.

This article first appeared in the September 2023 edition of the HealthPerks newsletter.