By Anya Costeloe, DO
In honor of thyroid cancer awareness month just wrapping up, I will give a brief overview of the epidemiology, diagnosis and treatment of thyroid cancer.
In terms of incidence, thyroid cancer is the fastest increasing cancer in the USA. The number of cases has tripled over the last 30 years. Women have a significantly higher incidence of thyroid cancer than men; about 75% of thyroid cancers occur in women. Other risk factors for thyroid cancer include increasing age, history of radiation exposure (especially if at a young age), iodine deficiency and family history. Approximately 5-10% of thyroid cancers are hereditary. The four main types of thyroid cancer are papillary (60-70% of all thyroid cancers), follicular (10%), medullary (3%) and anaplastic (<1%).
The US Preventative Medicine Task force recommended against routine screening for thyroid cancer starting in May 2017. However, physical examination of the neck is still an important part of a yearly wellness exam and any palpable thyroid nodules should be further investigated with a thyroid ultrasound.
How does thyroid cancer present?
Thyroid cancer most commonly presents as a painless, palpable solitary nodule. It is typically asymptomatic but patients may present with a feeling of fullness in the neck, hoarseness, a change in voice quality, difficulty swallowing and tightness in the lower neck.
Thyroid stimulating hormone (TSH) level is a sensitive measure of hyperthyroidism or hypothyroidism, however, thyroid malignancy cannot be diagnosed or ruled out based on it. Hyperthyroidism can be caused by a “hot” nodule, meaning it is producing thyroid hormones and usually hot nodules are benign.
How is it diagnosed?
When a patients has a suspicious nodule, the first step in the diagnosis is a fine needle aspiration biopsy (FNA). A pathologist will look at the cells from the FNA to determine whether the nodule is malignant and determine what type of cancer is it. It is not uncommon for the FNA to be inconclusive, which means that cancer can’t be ruled out. Previously, these patients would have a total thyroidectomy. However, in 2011 a new test called the Afirma Thyroid FNA Analysis was created. This test reduces the diagnostic uncertainty in patients with inconclusive FNA results.
How do you treat thyroid cancer?
In almost all types of thyroid cancer except for thyroid lymphoma,the main treatment for is surgery . Usually a thyroidectomy is performed, but in some cases a thyroid lobectomy may be done, in which only half of the thyroid is taken out. If the cancer has spread to any lymph nodes, then a neck dissection will be done to remove those nodes.
After the thyroid is removed, patients need to take thyroid hormone replacement tablets because they no longer have the cells that make this hormone. In papillary and follicular types of thyroid cancer, replacement hormones are important because they tell your body that there are sufficient thyroid hormone levels. This prevents the re-growth of cancer cells.
Another form of treatment is radioactive iodine, which is taken up by thyroid cells after being swallowed in pill form. It is toxic to the thyroid cells. It is used in papillary and follicular types of cancer and it is usually used in addition to surgery.
What’s the prognosis for patients with thyroid cancer?
The prognosis for different kinds of thyroid cancer varies, however, thyroid cancer has a good prognosis overall, 98.2% survival at 5-years.
- For follicular and papillary cancers age is the most important prognostic factor and patients younger than 45 have a better prognosis.
- Age is not as important in medullary cancer. Patients with medullary cancer that has not spread beyond the thyroid have a 95% 10-year survival.
- Patients with medullary cancer that has spread to the lymph nodes have a 75% 10-year survival.
- Survival decreases dramatically if there are metastases, which is why early detection and treatment are so important.
Check out the following websites for more information about thyroid cancer:
Haugen, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. Jan 2016, 26(1): 1-133.
Anya Costeloe, DO is a first year otolaryngology resident at St. John Providence in Michigan. She was born in Russia and immigrated to the US when she was seven years old. Dr. Costeloe received a bachelor’s degree at University of Colorado, Boulder in molecular, cellular and developmental biology and in Spanish. She attended medical school at Western University of Health Sciences College of Osteopathic Medicine in California. Outside of medicine, Dr. Costeloe enjoys traveling, snowboarding, hiking and yoga.