CALCA and medullary thyroid gland carcinoma: Prognosis of MTC is relatively good with a 10-year survival rate ranging from 47% to 78%2,3 and even better in patients with CT doubling-time of more than 2 years.4 Within the past decade the prognosis has improved mainly because of earlier diagnosis and improvement in surgical procedures.5,6 Nevertheless, more than 50% of nonprophylactic thyroidectomized patients are not cured after surgery.5 In these cases residual tumour cells can be detected by measuring serum calcitonin alone or in combination with pentagastrin stimulation.