Understanding Anaplastic Thyroid Cancer: Maria E. Cabanillas, M.D.

Robert I. Haddad, MD, discusses strategies for managing recurrent metastatic thyroid cancer.

New studies show that thyroid cancer has more than tripled over the last four decades. It especially affects young and middle-aged women, causing about 2,000 deaths a year.

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Chapters

0:00 Introduction
0:50 Causes of Thyroid Cancer
1:30 Symptoms of Thyroid Cancer
1:47 Diagnosis for Thyroid Cancer
2:13 Treatment for Thyroid Cancer




Thyroid cancer is cancer that develops from the tissues of the thyroid gland.[1] It is a disease in which cells grow abnormally and have the potential to spread to other parts of the body.[7][8] Symptoms can include swelling or a lump in the neck.[1] Cancer can also occur in the thyroid after spread from other locations, in which case it is not classified as thyroid cancer.[3]

Risk factors include radiation exposure at a young age, having an enlarged thyroid, and family history.[1][2] The four main types are papillary thyroid cancer, follicular thyroid cancer, medullary thyroid cancer, and anaplastic thyroid cancer.[3] Diagnosis is often based on ultrasound and fine needle aspiration.[1] Screening people without symptoms and at normal risk for the disease is not recommended as of 2017.[9]

Treatment options may include surgery, radiation therapy including radioactive iodine, chemotherapy, thyroid hormone, targeted therapy, and watchful waiting.[1] Surgery may involve removing part or all of the thyroid.[3] Five-year survival rates are 98% in the United States.[4]

Globally as of 2015, 3.2 million people have thyroid cancer.[5] In 2012, 298,000 new cases occurred.[10] It most commonly is diagnosed between the ages of 35 and 65.[4] Women are affected more often than men.[4] Those of Asian descent are more commonly affected.[3] Rates have increased in the last few decades, which is believed to be due to better detection.[10] In 2015, it resulted in 31,900 deaths.[6] Most often, the first symptom of thyroid cancer is a nodule in the thyroid region of the neck.[11] However, up to 65% of adults have small nodules in their thyroids, but typically under 10% of these nodules are found to be cancerous.[12] Sometimes, the first sign is an enlarged lymph node. Later symptoms that can be present are pain in the anterior region of the neck and changes in voice due to an involvement of the recurrent laryngeal nerve.[citation needed]

Thyroid cancer is usually found in a euthyroid patient, but symptoms of hyperthyroidism or hypothyroidism may be associated with a large or metastatic, well-differentiated tumor. Thyroid nodules are of particular concern when they are found in those under the age of 20. The presentation of benign nodules at this age is less likely, thus the potential for malignancy is far greater.[citation needed]
Causes

Thyroid cancers are thought to be related to a number of environmental and genetic predisposing factors, but significant uncertainty remains regarding their causes.[citation needed]

Environmental exposure to ionizing radiation from both natural background sources and artificial sources is suspected to play a significant role, and significantly increased rates of thyroid cancer occur in those exposed to mantlefield radiation for lymphoma, and those exposed to iodine-131 following the Chernobyl,[13] Fukushima, Kyshtym, and Windscale[14] nuclear disasters.[15] Thyroiditis and other thyroid diseases also predispose to thyroid cancer.[14][16]

Genetic causes include multiple endocrine neoplasia type 2, which markedly increases rates, particularly of the rarer medullary form of the disease.[17]
Diagnosis
Further information: Thyroid nodule
Micrograph of a lymph node with papillary thyroid carcinoma

After a thyroid nodule is found during a physical examination, a referral to an endocrinologist or a thyroidologist may occur. Most commonly, an ultrasound is performed to confirm the presence of a nodule and assess the status of the whole gland. Some ultrasound results may report a TI-RADS or TIRADS score to categorize the risk of malignancy.[18] Measurement of thyroid stimulating hormone, free and/or total triiodothyronine (T3) and thyroxine (T4) levels, and antithyroid antibodies will help decide if a functional thyroid disease such as Hashimoto's thyroiditis is present, a known cause of a benign nodular goiter.[19] a thyroid scan, performed often in conjunction with a radioactive iodine uptake test may be used to determine whether a nodule is "hot" or "cold"[20] which may help to make a decision whether to perform a biopsy of the nodule.[21] Measurement of calcitonin is necessary to exclude the presence of medullary thyroid cancer. Finally, to achieve a definitive diagnosis before deciding on treatment, a fine needle aspiration cytology test may be performed and reported according to the Bethesda system.[22]

After diagnosis, to understand potential for spread of disease, or for follow up monitoring after surgery, a whole body I-131 or I-123 radioactive iodine scan may be performed.[23]

In adults without symptoms, screening for thyroid cancer is not recommended.[24]