Thyroid Cancer

Thyroid cancer starts in the thyroid gland, a small butterfly-shaped gland in the front of your neck. The thyroid makes hormones that help control your metabolism, heart rate, blood pressure, and body temperature.

Many thyroid cancers grow slowly and respond very well to treatment. When found and treated, most people have an excellent outlook.

Types & Stages

There are several types of thyroid cancer:

• Papillary thyroid cancer. The most common type. It often grows slowly and usually responds well to treatment, even if it reaches nearby lymph nodes.
   
• Follicular thyroid cancer. A less common type that more often affects older adults. It can spread to the lungs or bones.
   
• Hurthle cell thyroid cancer. A rare type that can be more aggressive and may spread to the neck and other areas.
   
• Poorly differentiated thyroid cancer. A rare type that tends to grow faster and may not respond to usual treatments.
   
• Anaplastic thyroid cancer. A rare, fast-growing type that can be hard to treat. It is more common in older adults.
   
• Medullary thyroid cancer. A rare type that begins in special thyroid cells. Some cases are linked to an inherited gene change (called RET).
   
• Other rare types. Thyroid lymphoma and thyroid sarcoma are very rare.

Doctors don't always describe thyroid cancer with a complex stage. Instead, they consider the type of cancer, the tumor's size, whether it has spread to lymph nodes or other parts of the body, and sometimes the person's age. This helps guide treatment.

Signs & Symptoms

Thyroid cancer often causes no symptoms early on. As it grows, you may notice:

• A lump or swelling in the neck
• A feeling that shirt collars are getting tight
• Voice changes or hoarseness
• Trouble swallowing
• Swollen lymph nodes in the neck
• Pain in the neck or throat

Many of these symptoms can be caused by conditions that are not cancer. Still, if a symptom is new, lasting, or worries you, talk with a healthcare provider.

Diagnosis

Tests and procedures used to diagnose thyroid cancer may include:

• Physical exam. Your doctor feels your neck for lumps or changes in the thyroid.
   
• Blood tests. These check hormone levels to learn how your thyroid is working.
   
• Ultrasound. This imaging test shows the size and features of a thyroid nodule and can help check nearby lymph nodes.
   
• Fine-needle aspiration biopsy. A thin needle removes a small sample of cells from the nodule, often guided by ultrasound. A pathologist then examines the sample.
   
• Radioactive iodine scan. This may be used after surgery for some cancers to look for any remaining thyroid cells.
   
• Other imaging tests. A CT or MRI scan may be used when needed to see whether the cancer has spread.
   
• Genetic counseling and testing. For medullary thyroid cancer, your doctor may suggest meeting with a genetic counselor, since some cases are inherited.

Treatment

Treatment depends on the type and stage of the cancer, your overall health, and your preferences. Your care team can help explain the benefits and risks of each option.

• Active surveillance. Some very small papillary cancers may be closely watched instead of treated right away, using regular checkups, blood tests, and ultrasounds.
   
• Surgery. This is the most common treatment. The surgeon may remove the entire thyroid or only part of it. Nearby lymph nodes may also be removed if needed.
   
• Radioactive iodine. In select cases after surgery, this treatment helps destroy any remaining thyroid tissue or small areas of cancer.
   
• External beam radiation. This may be used in select cases, such as more advanced cancer, to help lower the chance that it comes back.
   
• Thyroid hormone therapy. After treatment, you may take a daily pill to replace the hormones your thyroid would normally make.

Clinical trials may also be an option. These studies test new treatments or new ways to use current ones. Ask your care team whether a clinical trial may be right for you.

Causes & Risk Factors

The exact cause of thyroid cancer is not always known. Some factors may raise the risk, including:

• Being female. Thyroid cancer is more common in women.
   
• Age. It can occur at any age but is most common from the thirties through the sixties.
   
• Radiation exposure. Radiation to the head or neck, or fallout from nuclear accidents, can increase risk.
   
• Inherited syndromes. Certain genetic conditions raise the risk, including RET-related medullary thyroid cancer and multiple endocrine neoplasia, type 2 (MEN2).
   
• Family history. Having a close relative with thyroid cancer can increase your risk.
   
• Excess body weight. Carrying extra weight is linked to a higher risk.
   
• Iodine in the diet. Low iodine intake is linked to follicular thyroid cancer, while high iodine intake is linked to papillary thyroid cancer.

Having a risk factor does not mean you will develop thyroid cancer, and many people with the disease have no clear risk factors. Talk with your healthcare provider about your personal risk.

Screening

Routine screening for thyroid cancer is not recommended for most people.

Even so, many thyroid cancers are found early. They are often noticed when a person feels a lump or swelling in the neck, during a routine checkup, or on imaging tests done for another health reason.

If you notice a lump in your neck or other symptoms that do not go away, talk with a healthcare provider about whether further evaluation is needed.

This information is for general education only and is not a substitute for medical advice. Please consult a qualified healthcare provider for diagnosis, treatment recommendations, and guidance based on your personal health history.