From the Yale School of Medicine, New Haven, CT.
ABSTRACT
• Objective: To review management of papillary thyroid cancer.
• Methods: Review of the literature.
• Results: Papillary thyroid cancer is the most common endocrine malignancy. The standard treatment for papillary thyroid cancer is thyroidectomy. Adjuvant therapy includes lifelong thyroid-stimulating hormone suppression and radioiodine therapy. Local recurrence is common and is normally treated with surgery and/or radioiodine. Metastatic radioiodine-resistant disease is a more infrequent event.
• Conclusion: The incidence of papillary thyroid cancer is rapidly increasing. Surgery remains the cornerstone of treatment.
Papillary thyroid cancer is the most common endocrine malignancy and accounts for the majority of cancers of the thyroid. The incidence of papillary thyroid cancer is rapidly increasing [1]. Although increasing detection has been proposed as a possible factor [2], some studies reject this hypothesis, reporting increase in the incidence of larger tumors [3]. Papillary thyroid cancer is characterized by a low mortality but a high recurrence rate [1], posing challenges not only to the endocrinologist and oncologist but also to the general practitioner.
The most frequent presentation of papillary thyroid cancer is a palpable thyroid nodule, cervical lymphadenopathy, or incidental detection on imaging. Locally advanced disease can present with hoarseness or voice alteration. Common risks factors include history of radiation exposure during childhood (the most important risk factor), thyroid cancer in a first-degree relative, family history of a thyroid cancer syndrome (such as Werner syndrome, Cowden syndrome, Carney complex, or familial polyposis), and female sex (2.5:1). Thyroid nodules in the context of an autoimmune thyroiditis may have a higher risk of malignancy [4].
CASE STUDY
Initial Presentation
A 49-year-old man with no significant past medical history presents with a painless mass in the anterior part of his neck.
History, Physical Examination, and Initial Investigations
He has no other symptoms, no weight changes, no history of radiation exposure to the neck, and no family history of malignancy. Physical exam shows a mass in the left thyroid lobe. There is no evidence of cardiac arrhythmias, tremors, or ophthalmologic abnormalities. Thyroid-stimulating hormone (TSH) level is 2.8 mIU/L (normal range, 0.4–4.5 mIU/L) and free thyroxine (T4) level is 1.1 ng/dL (normal range, 0.8–1.5 ng/dL). An ultrasound scan of the neck shows enlargement of the left lobe of thyroid gland, containing multiple complex lesions, the largest measuring 2 x 3 cm, with calcification as well as 3 enlarged lymph nodes in the left level IV. Fine-needle aspiration of the thyroid mass is positive for papillary carcinoma.
• What is the approach to the initial evaluation of a thyroid nodule?
Initial diagnostic evaluation includes history, physical examination, and TSH measurement; nonfunctioning nodules, associated with normal or high values of TSH, carry a higher risk of malignancy [5]. Cervical ultrasound should be performed in all patients with nodules. Fine-needle aspiration (FNA) should be used to evaluate nonfunctioning nodules > 1 cm or subcentimeter nodules with suspicious ultrasound features or if the patient has major risk factors (history of ionizing radiation exposure, external beam radiation exposure, family or personal history of papillary thyroid cancer, or FDG-PET [fluorinated glucose positron emission tomography]–positive thyroid nodules). Scintigraphy can be used to evaluate the need for ultrasound and FNA in patients with low TSH values [6,7]; hyperfunctioning nodules are at low risk for malignancy and do not require biopsy.