Endocrine Abstracts

Abstract: Medullary thyroid cancer (MTC) is a highly aggressive neuroendocrine tumour originating in the thyroid parafollicular cells. Calcitonin measurement and RET gene ascertainment have been used as markers for early diagnosis of MTC. Since pentagastrin is not available, calcium stimulation test helps to preclude ‘gray zone’ values of basal calcitonin, diagnose minimal residual disease and help the early diagnosis of C cell hyperplasia.

Aim: To establish a gender specific threshold for positive calcium stimulation test as well as indication for thyroidectomy and therefore prevention of MTC through early diagnosis.

Materials and methods: We conducted the calcium stimulation test on a series of patients with either nodular goiter, single nodule, RET positive or history of MTC associated with elevation of basal calcitonin values. Calcium gluconate 25 mg/kg adapted on the ideal BMI was administered over 3 min under ECG monitoring. Blood was collected before, at 2; 5 and 10 min after calcium infusion. Calcitonin was measured using LIAISON XL assay.

Results: The ongoing test has been performed on 17 patients, aged (23–67), 11 M, 6 F. Mean calcitonin values were: basal=19.98 pg/ml (normal range: 1–11.8 pg/ml); at 2 min=209.159 pg/ml; at 5 min=143.619 pg/ml, at 10 min=100.557 pg/ml; 10 subjects had a significant 2 min stimulated calcitonin (>100 pg/ml) and were operated, 3 subjects had an intermediate response (53.31–81.7 pg/ml) and 4 patients had low stimulated values(<54 pg/ml) therefore they are to be followed up. C cell hyperplasia (CCH) and MTC was confirmed histologically in 4 out of 10 patients (2 CCH and 2 MTC); 2 subjects had benign nodular goiter and 2 papillary thyroid microcarcinomas. More results are expected.

Conclusions: Stimulated calcitonin may be useful in the early diagnosis and follow-up of MTC and could reduce false negative rate of basal calcitonin measurement.