Highly sensitive thyroglobulin measurements in differentiated thyroid carcinoma management.

Differentiated thyroid cancer is an infrequent disease with a generally good prognosis. The initial treatment is total thyroidectomy coupled with ablation of thyroid remnants by iodine-131. Because thyroid cells are the only source of thyroglobulin in the human body, the circulating thyroglobulin measurement is the basis of differentiated thyroid cancer follow-up. Due to suboptimal sensitivity in older assays, the thyroglobulin measurements after stimulation by endogenous or exogenous thyrotropin are still recommended for unmasking occult disease. However, the development of thyroglobulin assays with improved functional sensitivity allows us to detect small amounts of thyroid tissue even when thyrotropin is suppressed. As a consequence, undetectable thyroglobulin during thyroxine treatment is sufficient evidence to forgo thyrotropin stimulation in many cases, if a highly sensitive assay is employed. On the other hand, increasing concentrations in highly sensitive assays are an early and reliable indicator of recurrent disease. This will result in a limited follow-up protocol, warranting the detection of recurrences of differentiated thyroid cancer and reducing patient burden and medical costs.