Thyroid cancer is relatively rare. According to the National Cancer Institute, it is estimated that there were 43,720 new cases of thyroid cancer and an estimated 2,120 people died of this disease in 2023.
Thyroid cancer most commonly begins as a growth (called a nodule) in the thyroid gland, which is located in the lower, front part of your neck. Usually, the nodule does not cause any symptoms; although a large thyroid nodule may cause pain or difficulty swallowing or breathing.
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Frequent Symptoms
Many people who have thyroid cancer do not have symptoms. These cancers are often discovered incidentally by a primary care or family healthcare provider during a routine neck examination or by an imaging test performed for other purposes (for example, a CT scan of the neck or a carotid ultrasound).
If symptoms are present, the most common one is the presence of a new thyroid growth or swelling, called a thyroid nodule. A fine-needle aspiration biopsy is often used to determine if a thyroid nodule is malignant (cancerous) or benign (noncancerous).
Symptoms and signs that are suggestive of a malignant nodule:
- Rapid growth of the nodule within a short period of time
- Nodule that feels "stuck" or tightly attached to the surrounding tissue
- Presence of lymph node swelling in the neck on the same side as the nodule
Rare Symptoms
Uncommon symptoms of thyroid cancer include:
- Pain in the front of the neck where the thyroid gland is located may move or radiate up to the jaw or ears
- A persistent tickle in the throat
- Problems swallowing if the thyroid nodule gets too large and presses on your esophagus (the tube that connects your throat to your stomach)
- Problems breathing if the nodule gets too large and presses on your trachea (windpipe)
- A persistent cough without other cold symptoms
- Hoarseness, if cancer invades the nerve the controls the vocal cords
Medullary Thyroid Cancer
With medullary thyroid cancer, which accounts for only 1 to 2% of all thyroid cancers, a person may experience symptoms like diarrhea, itching, and flushing if cancer has spread throughout the body.
These symptoms occur as a result of the production of calcitonin, which is a hormone made by thyroid "C" cells. Medullary thyroid cancer originates from these "C" cells, unlike the other types of thyroid cancer which originate from thyroid follicular cells (the cells that make thyroid hormone).
Complications
Thyroid cancer that metastasizes (spreads) outside of the neck is not typical, but it does happen if the tumor is not detected and treated early.
Moreover, it's worth mentioning that metastasis is most likely to occur with anaplastic thyroid cancer, which is a very rare, but aggressive type of thyroid cancer, accounting for less than 1% of all cases. Symptoms of anaplastic thyroid cancer include a rapidly growing neck lump that is large and firm, as well as hoarseness, problems swallowing and problems breathing.
Lung and Bone Metastasis
If there is any distant spread with thyroid cancer, the most common organs are the lungs and bones.
- Lung metastasis may cause a variety of symptoms like trouble breathing, shortness of breath, chest pain, or cough.
- Bone metastasis may cause bony pain, fractures, and spinal cord compression.
Brain Metastasis
Even rarer, thyroid cancer may spread to the brain. Experts estimate that this occurs in 0.1 to 5% of all cases of papillary thyroid cancer (the most common type of thyroid cancer).
Symptoms of brain metastasis vary according to where the metastatic lesion(s) are located in the brain. For example, in one case study in Head and Neck Oncology, a 75-year old woman developed gradually worsening dizziness, headaches, and vomiting and was found to have metastatic thyroid cancer to an area of her brain called the cerebellum (a region of the brain that helps control movement and coordination).
When to See a Healthcare Provider
If you feel a new swelling or lump in your neck, or if an imaging test incidentally reveals a thyroid growth, it's important to schedule an appointment with your healthcare provider right away.
During your appointment, your healthcare provider will:
- Perform a physical examination, including a neck examination
- Order an ultrasound of your thyroid
- Check blood tests that may include a thyroid-stimulating hormone (TSH), free thyroxine (T4), and thyroid antibodies
Depending on the results of these tests, your primary care or family healthcare provider may refer you to a healthcare provider who specializes in thyroid care (called an endocrinologist). An endocrinologist may take another look at the thyroid nodule with ultrasound in his or her office and perform a fine-needle aspiration (FNA) biopsy to see whether cancer cells are present.
Thyroid Cancer Healthcare Provider Discussion Guide
Get our printable guide for your next healthcare provider's appointment to help you ask the right questions.
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The diagnosis of thyroid cancer has been on the rise both in the United States and worldwide, due in large part to the sophistication of high-resolution imaging tests. In other words, these thyroid nodules that would never have been found years ago are now being identified.
While the majority of these small nodules end up not being cancer, determining which ones are is key—this is because most thyroid cancers are curable, especially those that are small and have not spread.
On a final note, if you have a family history of medullary thyroid cancer, be sure to talk to your healthcare provider. Through a genetic counselor, you can undergo genetic testing to see if you carry the gene mutations connected to medullary thyroid cancer.