Search

Purpose: No genomic data have been put forth that prove beyond a shadow of doubt that sporadic medullary thyroid cancer (MTC) occurs in infancy, childhood, and/or adolescence. Methods: This was a retrospective comparative study of consecutive patients with MTC who had neck surgery at a tertiary center over a 30-year period. Results: Included were 1252 patients with MTC (337 hereditary and 915 sporadic), of whom 107 (8.5%) were operated before the age of 18 yrs. Only 4 (3.7%) of the 107 pediatric patients, aged 14, 16, 17 and 17 years, had sporadic MTC. These 4 patients, 3 of whom had been referred for completion surgery, revealed much larger thyroid tumors (medians of 20 mm vs. 1.5–5 mm) than the 103 pediatric patients with hereditary MTC. As for extrathyroid extension and nodal metastases, the 4 patients with sporadic MTC were more comparable to the 37 carriers of highest-risk mutations, 31 (84%) of whom were index patients with de novo disease, than to the 66 carriers of high-risk, intermediate-risk, or low-risk RET mutations (25–38% vs. 0–8%, and medians of 9–9.5 vs. 0 node metastases after dissection of more (medians of 72–91.5 vs. 4.5–9) nodes). Conclusion: Sporadic MTC, arising rarely, if ever, below the age of 14 years, is exceptional in infancy and childhood, and infrequent in adolescence. At diagnosis, it is almost as widely metastatic as hereditary MTC of the highest-risk category which almost always, like sporadic MTC, presents as de novo disease. [ABSTRACT FROM AUTHOR]

Medullary thyroid cancer (MTC) is the most frequent manifestation of multiple endocrine neoplasia type 2 (MEN2) that determines the oncological outcome. Germline mutations in the rearranged during transfection (RET) protooncogene, a tumor suppressor gene on chromosome 10q11.2, were identified 30 years ago as the genetic basis of MEN2 and published in 1993 and 1994. These seminal findings gave rise to the concept of prophylactic thyroidectomy for asymptomatic gene mutation carriers based on a positive RET gene test, which has become the standard of care ever since. Clinical genetic investigations showed genotype-phenotype correlations with respect to the individual gene mutation regarding the penetrance and onset of MTC and to a lesser extent also with respect to the other components of MEN2, pheochromocytoma and primary hyperparathyroidism. From this a clinically relevant risk stratification could be derived. Initially, the optimal timing of prophylactic thyroidectomy was primarily based on the RET genotype alone, which was not sufficient for a precise age recommendation and subsequently required additional consideration of calcitonin serum levels for fine tuning. Calcitonin levels first show the risk of lymph node metastasis when they exceed the upper normal limit of the assay independent of carrier age and RET mutation. Routine calcitonin screening of patients with nodular thyroid disease, screening of families on identification of MEN2 index patients, and pre-emptive thyroidectomy in carriers of gene mutations with normal calcitonin levels have led to the fact that nowadays, 30 years after the first description of the gene mutations causing the disease, the life-threatening hereditary MTC has become curable: a shining example for the success of translational transnational medical research for the benefit of patients. [ABSTRACT FROM AUTHOR]