Henry Ford Hospital Medical Journal


Doubling times of basal and stimulated calcitonin (CT) levels and of random carcinoembryonic antigen (CEA) levels were compared over time in 11 patients with residual medullary thyroid carcinoma (MTC)—five with the sporadic MTC and six with the hereditary MTC. Four patients with an indolent form of the disease showed little change in CT levels over three to eight years and little change in CEA doubling times (42 to 70+ months). Seven patients showing rapid progression of disease had CT doubling times of three to 11 months and CEA doubling times of two to 12 months (however, one patient showed no change in CEA). A twelfth patient had a marked increase in CT doubling during two separate periods of pregnancy and lactation. We conclude that both CT and CEA levels may be helpful prognostically in patients with residual MTC, and each should be determined at intervals. Doubling time calculations provide practical estimations whereby the effects of therapeutic approaches, pregnancy, and various environmental influences on the growth of MTC can be evaluated.