Background: Medullary thyroid carcinoma (MTC) metastasizes early into the regional lymph nodes, but distant metastases occur late. Modified radical neck dissection might improve the treatment results for occultly metastasizing MTC.
Methods: The authors report 23 patients after a minimal follow-up of 2 years (median, 36 months). There were 11 female and 12 male patients. The mean age was 43 years (+/- 13 years). The surgical technique included the meticulous dissection of all compartments of the neck, resulting in a unilateral or bilateral modified radical neck dissection with the complete removal of the lymphatic and fatty tissue between important anatomical structures. The surgical boundaries extended cranially to the mastoid, caudally to the brachiocephalic vein involving a transcervical mediastinal dissection, and laterally to the edge of the trapezoid muscle. Ten patients were treated bilaterally and 13 patients unilaterally.
Results: The basal calcitonin values of 18 of the 23 patients were postoperatively normalized with 4 patients having normal basal and pentagastrin-stimulated calcitonin levels. Five patients with persistently elevated basal serum calcitonin values had a marked reduction of the postoperative calcitonin levels compared with their preoperative concentrations. However, in these five patients histologic abnormalities precluded a surgical cure. The permanent complication rates were tolerable (4 of 33 neck dissections).
Conclusions: The microsurgically extended neck dissection can reduce basal and pentagastrin-stimulated serum calcitonin values to normal levels even after long intervals following primary thyroidectomy.