THE NEED OF CALCITONIN MEASUREMENTS AFTER THYROIDECTOMY IN PATIENTS WITH MULTIPLE ENDOCRINE NEOPLASIA TYPE 2A (MEN2A)

AUTHORS:
M. van den Berg (Utrecht, Netherlands) , D. van Beek (Utrecht, Netherlands) , M. van den Broek (Utrecht, Netherlands) , L. Lodewijk (Utrecht, Netherlands) , A. Verrijn Stuart (Utrecht, Netherlands) , S. Terwisscha van Scheltinga (Utrecht, Netherlands) , R. van Leeuwaarde (Utrecht, Netherlands) , I. Borel Rinkes (Utrecht, Netherlands) , G. Valk (Utrecht, Netherlands) , M. Vriens (Utrecht, Netherlands)
Background:
Thyroidectomy is recommended for patients with Multiple Endocrine Neoplasia type 2A (MEN2A). American Thyroid Association 2015 guidelines recommend follow-up of calcitonin values after thyroidectomy. The aim of this study is to determine the natural course of calcitonin levels after thyroidectomy in MEN2A patients.
Methods:
Patients with MEN2A who underwent total thyroidectomy between 1993-2019 and had multiple postoperative calcitonin measurements were retrospectively included from our referral center. Long-term serial calcitonin measurements and clinical outcomes were correlated to the first postoperative calcitonin and histopathology.
Results:
Fifty-two patients were included. The median age at thyroidectomy was 10 years (range 0-71). Histopathology showed normal thyroid tissue or C-cell hyperplasia (CCH) in 23 patients (44%) and MTC in 29 patients (56%). The median follow-up time was 12 years (range 3-30). Thirty-eight patients had an undetectable first postoperative calcitonin, seven within reference range and seven above reference range. Of the 38 patients with a postoperative undetectable calcitonin 82% remained undetectable. All 23 patients with normal thyroid tissue or CCH and first postoperative undetectable calcitonin remained undetectable. Of the 17 patients with MTC and undetectable first postoperative calcitonin 10 (59%) remained undetectable and none developed structural recurrence. Structural recurrence was seen in five patients; all had MTC and detectable or elevated postoperative calcitonin.
Conclusions:
The long-term serial calcitonin values remain undetectable in the majority of patients with an undetectable first postoperative calcitonin. Biochemical follow-up for patients without MTC and an undetectable first postoperative calcitonin seems unnecessary. For those with an undetectable first postoperative calcitonin and MTC further research is needed.