Which of the following statements regarding papillary thyroid carcinoma are true?

a. Seventy to 80% of new cases of thyroid carcinoma in the United States are of the papillary type

b. Total ipsilateral lobectomy and isthmus resection are adequate therapy for minimal thyroid carcinoma

c. Microscopic evidence of multicentric disease is present in 70% to 80% of cases

d. Nearly all patients less than 15 years of age have metastatic disease in local lymph nodes

Seventy to 80% of the 11,000 new patients with thyroid carcinoma diagnosed annually in the United States have papillary carcinoma. Papillary carcinomas of the thyroid include minimal thyroid carcinoma, intrathyroidal, and extrathyroidal (invasion through the true thyroid capsule) disease. Minimal thyroid carcinoma refers to those papillary carcinomas that are less than 1 cm in diameter and not associated with any clinically apparent lymph node metastases. In contrast to clinically significant papillary carcinomas, these are common and are found in 2% to 13% of adult thyroid glands serially sectioned after autopsy studies of individuals who have died from other causes. For tumors between 0.5 and 1 cm, a total lobectomy and isthmus resection are satisfactory treatment.

resection are satisfactory treatment. Most clinically significant papillary carcinomas are 1 to 4 cm in diameter and are contained within the thyroid capsule. Multicentricity is relatively common and can be found on gross sectioning of the thyroid gland in 20% to 30% of cases. Furthermore, after serial sectioning of the entire thyroid gland in patients with papillary carcinoma, microscopic foci are found in 70% to 80%. Local cervical lymph node metastases are found in about 30% of all patients with papillary carcinoma. The presence of lymph node metastases does not correlate as closely to the size of the tumor as it does to the age of the patient. The younger the patient, the greater the likelihood of metastatic lymph node involvement. Nearly all patients under 15 years of age have involved metastatic lymph nodes. The presence or absence of lymph node metastases in patients with intrathyroidal primary papillary carcinomas does not appear to have an appreciable effect on long-term survival if distant metastases are not present at the time of initial treatment.