Thyroid cancer is newly diagnosed in about 60,000 people each year in recent years. However it only causes about 2,000 deaths per year.
The most common form (papillary cancer) develops very slowly, and treatment is almost always successful when the cancer is detected early. A less common form (follicular cancer) also develops relatively slowly. Two less frequent forms of thyroid cancer (undifferentiated, or anaplastic, and medullary) are more serious.
Anyone can get thyroid cancer. However, one group in particular has a higher risk: people who have had radiation to the head or neck. From the 1920s to the 1960s, X-ray treatments were used for an enlarged thymus gland, inflamed tonsils and adenoids, ringworm, acne, and many other conditions. At that time, doctors thought the X-rays were safe. About 1 million Americans received the treatment, and some of these people will get thyroid cancer up to 40 or more years after receiving the treatment.
We now know that radiation therapy to the head or neck increases the chance of developing thyroid cancer later in life. (Radioactive iodine treatments and x-rays used for testing do not increase the risk of cancer.) Others at risk include a child or elderly person with a lump (nodule) in the thyroid. If a man has a thyroid nodule, it is more likely to be cancerous than if a woman has one.
Does thyroid cancer cause symptoms?
Thyroid cancer often presents as a lump or “nodule” in the thyroid gland that is found “incidentally.” Thyroid nodules usually do not cause any symptoms. Blood tests of thyroid functioning are usually normal in someone who has thyroid cancer, so thyroid blood tests are not helpful for diagnosing thyroid cancer.
Examination of the neck by a doctor is a common way in which thyroid nodules and thyroid cancer are found. Thyroid nodules may also be discovered incidentally on imaging tests like CT scans and neck sonograms done for completely unrelated reasons. It is very unusual for thyroid nodules or thyroid cancers to cause symptoms. However, if they do cause symptoms this could include pain in the neck, jaw, or ear. If a thyroid nodule is large enough to press on other structures in the neck, it may cause voice changes or difficulty with breathing or swallowing.
The important points to remember are that most thyroid cancers develop in thyroid nodules and generally do not cause symptoms, thyroid function tests are typically normal even when thyroid cancer is present, and the best way to find a thyroid nodule is to make sure that your doctor examines your neck as part of your periodic health examination.