The thyroid gland is a butterfly shaped gland that sits over our trachea as it enters our chest. Each lobe of this gland is on average 3-5 cm. in height and 2 cm. in width. Thyroid nodules are growths that occur within the gland, which are very common. Fifty-percent of women over the age of fifty will have a nodule, however 90 percent of these nodules will be benign.
What are the symptoms of a thyroid nodule?
Most thyroid nodules are asymptomatic, including normal thyroid hormone levels. Very rarely, if a thyroid nodule is large enough it can cause symptoms of a hoarse voice, difficulty breathing and swallowing, a pressure sensation in the throat, or neck pain. They are most commonly found on physician examination or as an incidental finding on other imaging studies of the neck, such as a carotid ultrasound or an MRI of the cervical spine.
Statistics on thyroid cancer
As stated above, only one in ten thyroid nodules will be cancer. There are approximately 45,000 new cases of thyroid cancer diagnosed every year. This makes it the number five most common cancer diagnosed in women, and it does not even rank in the top ten for men. The number of thyroid cancer associated deaths is also very low, as this diagnosis often carries a favorable diagnosis, even when diagnosed at late stages. Thyroid cancers and nodules are about three times more common in women. The peak age of occurrence for women is between 40-50 and for men it is 60-70.
Risk factors for thyroid cancer
Age, as discussed above, can be a risk factor. Radiation exposure as a child can be a risk factor. Radiation was used for many processes that have become obsolete, such acne treatment and the treatment of enlarged tonsils. The radiation exposure to the thyroid can later cause thyroid malignancy. Although Iodine deficiency is very rare in the U.S., it can stimulate nodule formation and also place you at a higher risk for thyroid cancer. There are a number of familial conditions that also increase your risk of thyroid cancers.
How is thyroid cancer diagnosed?
The diagnosis process begins with a dedicated ultrasound, which is the best modality to evaluate the thyroid. It allows us to see high risk features, such as microcalcifications, echogenicity, and the vascularity of the lesion. If one meets criteria for biopsy, a fine needle biopsy is first completed. According to our American Thyroid Association guidelines, all of these biopsies should be completed under ultrasound guidance to ensure that the proper tissue is sampled. Depending on the biopsy results, surgery or observation will be recommended. Often, we will only take out half of the thyroid to spare the need for thyroid hormone replacement. It is not uncommon in thyroid surgery to require completion thryoidectomy in a second staged procedure, because the diagnosis of the cancer cannot be made until the pathologist has an opportunity to carefully look at the nodule.
What are the types of thyroid cancer?
This is the most common thyroid cancer we see and it accounts for 80% of all thyroid cancers. It has the most favorable outcome with survival rate of 93% at five years at Stage III, which is when the cancer is found with regional metastases.
This is the second most common thyroid cancer that is seen a rate of 10%. This also carries a very favorable diagnosis.
This cancer can often be familial in nature and associated with some other syndromes such as a condition called MEN (multiple endocrine neoplasias). The treatment of this cancer is often more aggressive, but is still very treatable if caught in the early stages.
This is a rare very aggressive type of thyroid cancer that occurs in less that 2% of all thyroid cancers. Unlike other thyroid cancers, this is very resistant to any treatment and has a high mortality rate.
How do we treat thyroid cancer?
Surgical resection of the entire gland is the mainstay of treatment. Depending on the size of the tumor, radioactive iodine may be given. This is often administered a few weeks after surgery and allows for the destruction of any last cell of thyroid tissue that may have been left behind. There is most often no need for any other adjuvant chemotherapy or radiation treatments.
I am worried about a thyroid nodule, what should I do?
The first step is to start with your primary care provider. A careful examination of the neck is important. If it is then indicated, a thyroid ultrasound can be ordered. If necessary, your primary care physician can then refer you for the appropriate specialist.