A patient with MEN 2A syndrome is found to have a RET mutation at codon 634. According to the American Thyroid Association (ATA) risk category for prophylactic thyroidectomy, when should surgery be performed?
- A Within the first 6 months of life (highest risk category A)
- B By age 5 years (high risk category B)
- C Before age 5 years ideally by 3–5 years (ATA high-risk category) ✓
- D At the time calcitonin rises above the upper limit of normal (any age)
Correct answer: C. Before age 5 years ideally by 3–5 years (ATA high-risk category)
Explanation
ATA 2015 guidelines classify RET codon 634 mutations as 'high risk' (Category C), recommending prophylactic thyroidectomy by age 5 years, with some experts favouring age 3–5 years based on earliest reported medullary thyroid cancer in this codon. The 'highest risk' category D (codons 918, 883) requires surgery within 6 months of life. Category B (moderate risk) mutations may be managed with surveillance until calcitonin rises. Codon 634 is associated with MEN2A (pheochromocytoma, hyperparathyroidism) and carries significant penetrance for MTC by the third decade.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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