Thyroid nodules are extremely common – over half of people over 60 have one, according to the American Thyroid Association. Most of them, however, are benign with only 2-12 percent becoming cancerous.
The thyroid is a butterfly-shaped endocrine gland located in the lower front of the neck which produces hormones that control your metabolism. Lumps or bumps in this gland are called nodules. What causes them is not known, although iodine deficiency and inflammation of the thyroid can increase the risk of developing thyroid nodules.
Women are more likely than men to develop thyroid nodules, and are more frequently diagnosed with thyroid cancer according to the Canadian Cancer Society.
Changes in the thyroid may be seen or felt, but most thyroid nodules don’t cause symptoms. They are often discovered during a routine physical exam or via medical imaging, like ultrasound or computed tomography (CT) exams, performed for unrelated reasons. Sometimes the tissue in a nodule makes too much of the thyroid hormones causing hyperthyroidism, which can be seen by performing a thyroid-stimulating hormone (TSH) blood test. However, most thyroid nodules, including those that are cancerous, are actually non-functioning, meaning tests like TSH are normal.
It’s important to see your doctor if you have:
The only way to definitively determine if a thyroid nodule is cancerous is to examine it under a microscope. The most common method is called fine need aspiration (FNA) biopsy, where a very small needle is inserted into the thyroid nodule and cells are removed for microscopic examination. However, only a small percentage of nodules are cancerous, and, of those, an even smaller percentage requires treatment. Most thyroid cancers are curable and rarely cause life-threatening problems.
At Mayfair Diagnostics, we follow the American College of Radiology’s Thyroid Imaging, Reporting, and Data System (TI-RADS) for the classification and evaluation of thyroid nodules. Our thyroid ultrasound reports to your doctor describe the nodule’s features, assess the risk of malignancy, and help determine next steps, such as the need for FNA or ultrasound follow-up to monitor nodule growth or development of worrisome features.
The goal of TI-RADS is to help you and your doctor balance the benefit of identifying cancers that require treatment against the risk of biopsy and treatment of benign nodules or indolent cancers – cancers that are slow-growing and will almost certainly never be problematic.
Thyroid nodules and other thyroid conditions, such as goitre (enlarged thyroid) and inflammation of the thyroid, can increase the risk of thyroid cancer. Other risk factors include:
This exam is covered under your Alberta Health Care Insurance Plan and must be requested by a health care practitioner. To determine whether it’s appropriate for you, your doctor will often review your medical and family history, risk factors, how long symptoms have been present, and how they affect daily activities. If a thyroid ultrasound is indicated as a best next course of action, your doctor will provide you with a requisition and the appointment can be booked.
Brady, Dr. Bridget (2018) “Thyroid Nodules: Prevalence, Symptoms, Causes, Diagnosis, and Treatments.” www.endocrineweb.com. Accessed February 25, 2019.
Vaccarella, S., et al. (2016) “Worldwide Thyroid-Cancer Epidemic? The Increasing Impact of Overdiagnosis.” New England Journal of Medicine, 375;7: 614-17.