RESUMEN
CONTEXT: The preoperative routine measurement of basal serum thyrocalcitonin (CT) in candidates for thyroidectomy due to thyroid nodules is currently a subject of debate. OBJECTIVE: The objective of this study was to evaluate the role of systematic basal serum CT measurement in improving the diagnosis and surgical treatment of medullary thyroid carcinoma (MTC) in patients undergoing thyroidectomy for nodular thyroid disorders, regardless of preoperative CT levels. DESIGN: We determined basal serum CT levels in 2733 consecutive patients before thyroid surgery and performed a pentagastrin test in patients with hypercalcitoninemia. We correlated basal and stimulated CT levels with intraoperative and definitive histopathological findings, and we analyzed the impact of these results on surgical procedures. RESULTS: Twelve MTCs were found among the 43 patients with basal serum CT level of 10 pg/ml or greater. Two MTCs were present among the 2690 patients with normal CT levels. MTC was always present in patients with a basal CT of 60 pg/ml or greater. For CT levels ranging from 10 to 59 pg/ml, MTC was diagnosed in 11% of patients. When preoperative hypercalcitoninemia was present, total thyroidectomy associated with comprehensive intraoperative histopathological analysis allowed the intraoperative diagnosis of five latent, subclinical MTCs. The pentagastrin test gave no additional diagnostic information for the management of patients with elevated preoperative basal serum CT level. CONCLUSION: Routine measurement of CT in the preoperative work-up of nodular thyroid disorders is useful. This procedure improves intraoperative diagnosis of MTC and enables adapted initial surgery, the most determinant factor of treatment success.