Causes of Thyroid Cancer
There is often no definitive cause of well-differentiated thyroid cancer. It’s a combination of genetics and environmental factors. However, listed below are a few known risk factors for developing thyroid cancer:
Radiation
Radiation exposure—from previous medical treatments or from environmental disasters like power plant accidents or nuclear explosions—is a known risk factor for developing thyroid cancer. Head and neck radiation treatments during childhood have been associated with an increased risk of thyroid cancer; this risk is higher for larger doses and younger ages of a patient at the time of radiation treatment.
Family History
People with at least 2 first-degree relatives diagnosed with thyroid cancer are at an increased risk of developing thyroid cancer themselves. This risk factor applies to people regardless of whether or not they have a known genetic syndrome associated with thyroid cancer.
Inherited Medical Conditions
Patients with familial adenomatous polyposis (FAP), Cowden disease, or Carney complex type I may be at an increased risk of developing papillary or follicular thyroid cancer. Learn more about genetic mutations related to thyroid cancer.
Low-Iodine Diet
Although most people in the United States obtain enough iodine in their diet due to iodized table salt and other food products that contain iodine, low-iodine diets are common in other parts of the world. Diets low in iodine may increase the risk of follicular and papillary thyroid cancer, especially if a person has also experienced some radiation exposure.
Signs & Symptoms of Thyroid Cancer
Thyroid cancers are usually detected by patients or doctors when they feel a lump in the thyroid gland or when an imaging test for an unrelated condition shows a lump in the thyroid gland. Other rare signs and symptoms of thyroid cancer include:
- A lump or bump somewhere else in the neck.
A metastatic lymph node with a biopsy showing thyroid cancer is another way that thyroid cancer can be detected. - Change in voice.
Unlike benign tumors in the thyroid gland, thyroid cancers can invade the nerves to the voice box (larynx) or even the trachea and esophagus. This could lead to a hoarse voice. - Difficulty swallowing (dysphagia).
If thyroid tumors become very large (or invade surrounding structures), they can cause difficulty with swallowing.
It is important to note that a patient could have one or more of these symptoms and NOT have thyroid cancer. There are several non-cancerous causes of the same symptoms. That is why it is important for patients to go see a medical specialist if they are experiencing any of these symptoms.
