Medullary thyroid microcarcinoma recommendations for treatment - a single-center experience.

Abstract

Conflicting recommendations exist regarding lymph node (LN) surgery in microMTC (<or=10mm). This study aims to correlate biochemical and pathohistological findings in an attempt to define the characteristics of microMTC, thus allowing recommendations for LN surgery. Patients with elevated basal (bCT:>or=10pg/ml) and pentagastrin-stimulated calcitonin levels (sCT:>100pg/ml) were selected for initial surgery. None of the patient was a member of any known MTC family. Biochemical and morphological data of microMTC were compared with 146 patients with C-cell hyperplasia (CCH). MicroMTC (tumor diameter: 4.2+/-2.6mm; unifocal:68; multifocal:29) was documented in 97 of 159 (61%) MTC patients. In 11 (11%) patients, 1-19 LNs were involved. Correlating bCT and sCT levels neither predicted N-stage, nor differentiated between microMTC and CCH. The biochemical discrimination cannot be made between patients with CCH and MTC, and patients with MTC with/without LN metastasis. Thus, thyroidectomy and central neck dissection is indicated in patients with "mildly" elevated sCT levels (<560pg/ml) (LN positive: 1 of 37 patients [2.7%]). A lateral neck dissection may be added "on demand" (in the setting of measurable postoperative bCT and/or sCT levels indicating LN metastasis). Patients with "highly" elevated sCT (>or=560pg/ml) must be treated as "palpable" MTC (LN positive: 10 of 54 patients [18.5%]).