Appropriate surgical management for medullary thyroid carcinoma (MTC)
MTC accounts for < 5% of thyroid cancers but occurs as part of an inherited syndrome in 20% to 25% of cases. Thus, all patients with MTC should be considered for genetic testing. If the patient has multiple endocrine neoplasia type 2 (MEN 2) syndrome, a prophylactic thyroidectomy is indicated, and the specific mutation in the RET gene can help determine at what age the surgery should occur. Patients with MEN 2 should also be screened for pheochromocytoma and primary hyperparathyroidism so that these conditions can be surgically corrected prior to or concomitant with the thyroidectomy, respectively. Because medullary thyroid cancer is not sensitive to radioiodine or thyroid-stimulating hormone (TSH) suppression, a total thyroidectomy is indicated. Because of the high incidence of regional lymph node involvement, a central neck dissection is performed at the time of thyroidectomy. Some surgeons also advocate routine prophylactic ipsilateral or bilateral modified radical neck dissection at the initial surgery; however, despite this aggressive approach, biochemical cure (normalization of serum calcitonin) is uncommon in patients with positive nodes. In the latest ATA guidelines, the task force did not achieve consensus. Some recommend that lateral neck dissection should be performed selectively based on clinically or ultrasonographically abnormal nodes. Others consider basal serum calcitonin levels, recommending ipsilateral central and lateral neck dissection for levels > 20 pg/mL and bilateral lateral dissection for levels > 200 pg/mL.