Long-term Outcome of Prophylactic Thyroidectomy in Children Carrying RET Germline Mutations

Background: A comprehensive assessment has not been undertaken of long-term outcomes in children carrying germline RET mutations and undergoing prophylactic thyroidectomy with the aim of preventing medullary thyroid cancer (MTC).

Methods: A retrospective outcome study (1994-2017) of prophylactic thyroidectomy in children, with and without central node dissection, was performed at a tertiary surgical centre.

Results: Some 167 children underwent prophylactic thyroidectomy, 109 without and 58 with concomitant central node dissection. In the highest-risk mutational category, MTC was found in five of six children (83 per cent) aged 3 years or less. In the high-risk category, MTC was present in six of 20 children (30 per cent) aged 3 years or less, 16 of 36 (44 per cent) aged 4-6 years, and 11 of 16 (69 per cent) aged 7-12 years (P = 0·081). In the moderate-risk category, MTC was seen in one of nine children (11 per cent) aged 3 years or less, one of 26 (4 per cent) aged 4-6 years, three of 26 (12 per cent) aged 7-12 years, and seven of 16 (44 per cent) aged 13-18 years (P = 0·006). Postoperative hypoparathyroidism was more frequent in older children (32 per cent in the oldest age group versus 3 per cent in the youngest; P = 0·002), whether or not central node dissection was carried out. Three children developed recurrent laryngeal nerve palsy; all had undergone central node dissection (P = 0·040). All complications resolved within 6 months. Postoperative normalization of calcitonin serum levels was achieved in 114 (99·1 per cent) of 115 children with raised preoperative values. No residual structural disease or recurrence was observed.

Conclusion: Early prophylactic thyroidectomy is a viable surgical concept in experienced hands, sparing older children the postoperative morbidity associated with delayed neck surgery.