Timing of total thyroidectomy in RET gene carriers <18 years of age

Objectives: To verify the timing of thyroidectomy in gene carriers RET (GC) <18 years. Methods: We collected data on RET mutation carriers from 14 different Italian Centers for a total of 121 RET GC <18 years. Basal serum CT levels were available in 111 cases. Results: Sixty-four patients had undetectable basal CT levels and 30/64 were surgically treated. At histology 16 cases were either negative (n=2) or presented CCH (n=14). Fourteen cases were found to have microMTC (T1N0M0). One patient was lost at follow-up while all the others were disease free. Forty-seven patients had elevated basal CT levels (range 6-7250 pg/ml). Total thyroidectomy was performed in 44 cases: 10 were found to have CCH and 34 MTC at histology. In the latter group 28 patients were cured, 5 had a persistent disease and 1 was lost at follow-up. When basal CT was <80 pg/ml, the MTC was intrathyroidal, no metastases were present and all patients were cured (mean follow up 112±71 months). For CT values >80 pg/ml we had cases with biochemical or morphological persistent disease. A total of 37 patients (mean follow up 31±21 months) were not and are under follow-up. Conclusions: Our data indicate that the surgical treatment of GC <18 years can be postponed if the basal CT is undectable or in the normal range. In this series the “safe” cut-off level of basal CT was 80 pg/ml but appropriate institutional cut-off should be identified.