What Is Thyroid Cancer & What Are My Risks?
Have you ever wondered why your primary care physician feels around the base of your neck during a check-up? If you’ve scheduled an appointment for a sore throat, hoarseness, or difficulty swallowing, your provider may use the opportunity to rule out abnormal bumps or swelling of the thyroid gland — a telltale sign of thyroid cancer. This Thyroid Cancer Awareness Month, learn about the different forms of this common type of cancer, its risk factors, and how to detect it.
Statistics & Types
According to the American Cancer Society, an estimated 43,720 new cases of thyroid cancer will be diagnosed in the U.S. in 2023 with an estimated 2,120 lives claimed. Prognosis may vary according to the type of thyroid cancer, but generally, it is treatable — in fact, the American Association for Cancer Research reports a 98.5% survival rate over five years. Thyroid cancer may develop in the following forms:
- Papillary cancer — This form of differentiated thyroid cancer — also known as papillary carcinomas or papillary adenocarcinomas — accounts for about 80% of thyroid cancers, developing slowly and usually in only one lobe of the thyroid gland. Papillary cancer can usually be treated successfully and is rarely fatal.
- Follicular cancer — Another form of differentiated thyroid cancer, follicular cancer is the second-most common form of thyroid cancer, accounting for roughly 10% of diagnoses. Follicular cancer usually doesn’t spread to the lymph nodes but can spread to other parts of the body like the lungs and bones. More common in populations with low-iodine diets, prognosis for follicular cancer isn’t as promising as papillary cancer, but the American Cancer Society reports prognosis is still good in most cases.
- Hürthle cell cancer — Also known as oxyphil cell carcinoma, this differentiated thyroid cancer is harder to detect and treat, accounting for about 3% of diagnoses.
- Medullary thyroid carcinoma — Making up about 4% of cases, medullary thyroid carcinoma (MTC) develops from C cells of the thyroid gland and can sometimes spread to the lymph nodes, lungs, or liver before a thyroid nodule is found, making it more difficult to detect and treat. Medullary thyroid carcinoma comes in two forms:
- Sporadic MTC, a non-hereditary form that makes up 80% of MTC cases, occurs mostly in older adults, and often affects just one thyroid lobe.
- Familial MTC, an inherited form of MTC that often develops in childhood or early adulthood, spreads early, affects several areas of both lobes, and is often linked with an increased risk of other types of tumors.
- Anaplastic thyroid cancer — Also known as undifferentiated thyroid cancer, anaplastic thyroid cancer is rare, accounting for just 2% of diagnoses, and is thought to sometimes develop from existing papillary or follicular cancer. Anaplastic thyroid cancer is aggressive, spreading quickly into the neck and other parts of the body, and is difficult to treat.
What Are My Risk Factors?
Though the exact cause of thyroid cancer remains unknown, researchers have identified several risk factors that may be linked to the disease. For example, women are 3 times more likely to develop thyroid cancer than men — again, for unclear reasons. Many hereditary conditions are also believed to carry an increased risk, as does family history. These factors may be impossible to manage, but some controllable factors include:
- Radiation exposure
- Low amounts of iodine in diet
- Overweight and obesity
Can Thyroid Cancer Be Detected Early?
Though thyroid cancer may sometimes be asymptomatic, many patients experience some early warning signs, the most common of which is a lump or swelling in the neck. Other patients may experience pain extending up to the ears, hoarseness in the throat, persistent voice changes, trouble swallowing or breathing, and a constant cough not caused by a cold. While these symptoms may not necessarily point to a cancer diagnosis, they could still point to an underlying thyroid disorder. If you experience these symptoms, schedule an appointment with your provider immediately.
Most cases are detected during routine check-ups when physicians feel neck lumps or nodules. Others can be found through imaging, blood tests, or thyroid ultrasounds, though these forms of testing aren’t recommended for those at average risk (i.e., people without a family history or other high risk). Treatments may include various forms of surgery — including a lobectomy, thyroidectomy, and lymph node removal — radioiodine therapy, hormone therapy, external beam radiation, chemotherapy, and targeted drug therapy.