Calcitonin (Thyrocalcitonin)

Detection and confirmation C-cell hyperplasia (the precursor of medullary carcinoma of thyroid) as well as a tumor marker for diagnosis and management of medullary carcinoma of the thyroid gland. Preoperative serum calcitonin is reported to roughly correlate with tumor weight or extent of disease; therefore, postoperative levels also have prognostic application. The doubling time of serum levels correlates with a recurrence. Multiple endocrine neoplasia (MEN) type II includes medullary carcinoma of the thyroid, hyperparathyroidism, and pheochromocytoma (Sipple syndrome). MEN type IIB includes medullary carcinoma of the thyroid, pheochromocytoma, mucosal neuromas, marfanoid habitus, and intestinal ganglioneuromatosis. An important use of calcitonin assay is in follow-up of patients with medullary carcinoma and work-up of their families to detect early, subclinical cases. Indications for calcitonin assay include family history of unspecified type of thyroid cancer, calcified thyroid mass, thyroid tumor associated with hypercalcemia and/or pheochromocytoma, amyloid-containing metastatic carcinoma with unknown primary site and the presence of mucosal neuromas