Intraoperative high-dose calcium stimulation test in patients with sporadic medullary thyroid carcinoma is highly accurate in predicting lateral neck metastases.

Abstract

Intraoperative measurement of calcitonin is not highly accurate in predicting the completeness of the operative resection after total thyroidectomy combined with central neck dissection (TT-CND) in patients with medullary thyroid carcinoma (MTC). We evaluated whether an intraoperative, high-dose calcium stimulation test (IO-CST) after TT-CND can predict lateral neck involvement. Eleven patients who underwent primary operation for sporadic MTC were included. High-dose (25 mg/kg) calcium gluconate was administered after TT-CND with calcitonin measured at 2, 5, and 10 minutes after the calcium gluconate infusion. There were 2 males and 9 females (mean age, 51 years; range, 18-88). Three patients showed lateral neck metastases. At a mean follow-up of 7.0 months (range, 2-10), 1 patient showed distant metastases and 1 a slightly increased calcitonin level. After IO-CST, serum calcitonin increased in all the 3 patients with lateral neck metastases, and it remained unchanged or decreased in the other patients without lateral neck metastases. Percent variation of serum calcitonin after IO-CST was 92% in patients with lateral neck metastases and -3.1 ± 4.9% in patients without lateral neck metastases. Calcitonin measurement after IO-CST in patients with sporadic MTC can be highly accurate in predicting lateral neck nodes involvement. These results could represent a stimulus toward the development of a quick calcitonin assay.