[Recommendation for Calcitonin Screening in Nodular Goiter].

Medullary thyroid cancer (MTC) arises from parafollicular C cells of the thyroid gland and is characterized by a calcitonin secretion. Basal calcitonin correlates with the tumor mass and is used as highly sensitive and specific tumor marker for MTC. Based on former assays, unspecific calcitonin increase has frequently been seen in Hashimoto's thyroiditis, kidney insufficiency, proton pump inhibitors etc. This phenomenon is now less often seen with modern assays. The consequent use of calcitonin measurement in nodular goiter helps to identify the rare MTC at an early stage. The best cut-off values to differentiate micro-MTC from C-cell hyperplasia and other unspecific calcitonin elevations were achieved by the use of a 30 pg/ml and a 60 pg/ml threshold in women and men, respectively. This approach is not less sensitive than formerly used pentagastrin stimulation. A calcitonin value > 100 pg/ml is nearly 100 % predictive for MTC. Therefore, the Thyroid Section of the German Society of Endocrinology recommends a thyroidectomy in woman with serum calcitonin values > 30 pg/ml (grey zone 20 - 30 pg/ml) and in man with serum calcitonin values > 60 pg/ml (grey zone 30 -60 pg/ml). Lower calcitonin values should be re-evaluated in intervals of 3 - 6 months; rising calcitonin levels may indicate an MTC. In this case, thyroid operation should be performed. The cure rate of MTC with calcitonin values < 100 pg/ml is nearly 100 % done by high volume surgeons.