INTEREST OF ROUTINE MEASUREMENT OF SERUM CALCITONIN - STUDY IN A LARGE SERIES OF THYROIDECTOMIZED PATIENTS

The aim of our study was to assess the ability of routine calcitonin ( CT) measurement to improve the preoperative diagnosis of medullary thy roid carcinoma (MTC) in nodular thyroid diseases. We systematically de termined basal CT in 1167 patients before thyroid surgery and performe d a pentagastrin (Pg) CT stimulation test in 121 of these patients who se basal CT level was normal. Sixteen MTC (1.37%) were found on histop athological examination of surgical specimens: 14 in the 34 patients ( 41.1%) with abnormal basal CT levels and 2 in the 1133 patients with n ormal basal CT levels (0.17%). An abnormal increase in Pg-stimulated C T was observed in 7 of the 121 patients tested and was related to micr oscopic MTC in 2 cases. Among 1167 thyroidectomized patients with nodu lar thyroid diseases, the prevalence of MTC was 1.37% and reached 41.1 % when the basal CT level was abnormal (3% of the patients). CT evalua tion detected MTC, whereas other procedures, such as fine needle aspir ation cytology, failed, thus allowing early radical surgery. CT measur ement should thus become a routine part of the diagnostic evaluation o f nodular thyroid diseases.