Medullary Thyroid Cancer in Children with RET Germline Mutation Other Than M918T, C634, and A883F

This protocol addresses medullary thyroid cancer (MTC) in paediatric patients who carry a germline RET codon mutation that falls outside the three highest-risk variants — specifically, mutations other than M918T, C634, and A883F.

Clinical scenario

Patients in this group — classified in the ATA-MOD risk category — are children with a confirmed RET germline mutation that is not M918T, C634, or A883F. The ATA-MOD category is distinct from ATA-HST (M918T / MEN2B) and ATA-H (C634, A883F), and carries its own age-specific management considerations.

Approach

Management for ATA-MOD children involves a surgical intervention — the timing of which is guided primarily by a specific biochemical parameter rather than a fixed age threshold.

The complete protocol — including the full decision algorithm, surveillance intervals, and criteria for timing — is available via the structured regimen below.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1089/thy.2014.0335

The ATA-HST category includes patients with MEN2B and the RET codon M918T mutation, the ATA-H category includes patients with RET codon C634 mutations and the RET codon A883F mutation, and the ATA-MOD category includes patients with RET codon mutations other than M918T, C634, and A883F.

Children in the ATA-MOD category should have a thyroidectomy in childhood or young adulthood, the timing depending primarily on serum Ctn levels.

The timing of thyroidectomy should be based on the detection of an elevated serum Ctn level; however, 6-month or annual evaluations may extend to several years or decades.

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