Genetics of Endocrine and Neuroendocrine Neoplasias (PDQ®): Genetics - Health Professional Information [NCI] - Multiple Endocrine Neoplasia Type 2
Table 5. American Thyroid Association Medullary Thyroid Cancer Risk Stratification and Management Guidelinesa continued...
Level of evidence: 5
Screening of at-risk individuals in kindreds without an identifiableRETmutation
MEN2A: Risk-reducing thyroidectomy is not routinely offered to at-risk individuals if the disorder is unconfirmed. The screening protocol for MTC is an annual calcitonin stimulation test; however, caution must be used in interpreting test results because CCH that is not a precursor to MTC occurs in about 5% of the population.[12,13,205] In addition, there is significant risk of false-negative test results in patients younger than 15 years. Screening for pheochromocytoma and parathyroid disease is the same as described above.
FMTC: Annual screening for MTC, as for MEN2A.
Level of evidence: 5
Treatment for those with MTC
Standard treatment for adults with MTC is surgical removal of the entire thyroid gland, including the posterior capsule, and central lymph node dissection. Children with MEN2B having prophylactic thyroidectomy within the first year of life may not require central neck dissection unless there is radiological evidence of nodal disease. Likewise, children with MEN2A or FMTC having prophylactic thyroidectomy before 3 to 5 years of age should not have a central neck dissection in the absence of radiological evidence of metastatic lymph node involvement. The ATA also recommends that MEN2A and FMTC patients older than 5 years or asymptomatic MEN2B patients older than 1 year have a preoperative basal calcitonin test and neck ultrasound. A basal calcitonin level over 40 pg/mL or thyroid nodules greater than or equal to 5 mm requires further evaluation, as the patient may have more extensive disease requiring nodal dissection. If an MEN2B patient older than 1 year has nodules smaller than 5 mm or basal calcitonin lower than 40 pg/mL, then total thyroidectomy may be sufficient therapy, but the ATA task force favors prophylactic central neck dissection without lateral compartment dissection in the absence of radiographic evidence of metastatic involvement (level C recommendation). See Table 6 for complete details.
Table 6. American Thyroid Association Management Guidelines for MEN2A/FMTC and MEN2Ba
|Syndrome||Age (y)||Nodal Disease||Basal Calcitonin (pg/mL)b||Nodule ≥ 5mm||Lymph Node Dissection||Strength of Recommendationc|
|FMTC = familial medullary thyroid carcinoma; MEN2 = multiple endocrine neoplasia type 2.|
|a Adapted from Kloos et al.|
|b Basal calcitonin values are applicable in patients older than 6 months.|
|c Based on grading definitions established by theU.S. Preventive Services Task Force.|