Anaplastic Thyroid Carcinoma: Clinical Aspects

Abstract

Anaplastic thyroid carcinoma (ATC) is more common in women than in men, with a ratio of 1.9:1. The tumor occurs in older individuals and has a median (mean) age of 69 (66.5) years. ATC often exists coincidentally with, or in patients with a history of, differentiated thyroid cancer, suggesting a dedifferentiated process. ATC comprises only 3.8 % of thyroid cancers worldwide and is seen more frequently in regions of iodine deficiency. Iodine supplementation has reduced the frequency by 40–80 %. ATC usually presents with the sudden onset of a neck mass. The tumor produces both airway and esophageal obstructive symptoms including dyspnea, dysphagia, hoarseness (due to recurrent laryngeal nerve involvement), pain, cough, and hemoptysis, and death occurs shortly thereafter. The median tumor size at onset is 6.8 cm but may be as large as 25 cm. Initial imaging is required to assess the extent of disease, and FDG-PET is particularly helpful in locating disease locations. Metastatic disease at presentation occurs commonly, with lung and mediastinal lesions being identified most frequently. Other sites include the bone, liver, brain, heart, adrenal glands, and kidney, many of these being sites rarely affected by differentiated thyroid cancers. Initial evaluation should include not only anatomic staging but an assessment of the patient’s performance status, after which, a realistic discussion of the patient’s therapeutic options and desire for aggressive versus palliative management should be held. Restaging and goals of care should be reassessed after initial therapy and periodically thereafter. Causes of death are both from local obstructive complications and distant metastases.