DETERMINATIVE FACTORS OF BIOCHEMICAL CURE AFTER PRIMARY AND REOPERATIVE SURGERY FOR SPORADIC MEDULLARY-THYROID CARCINOMA

Normalization of calcitonin levels after surgery has been regarded as the most powerful prognostic factor for medullary thyroid carcinoma (M TC). Although the prognosis of patients with persistent hypercalcitoni nemia may be acceptable, the biochemical cure rate can be improved by new microdissection techniques. This raises certain questions: Can ext ension of locoregional lymphadenectomy(LA) further improve biochemical cure and survival after primary or reoperative MTC surgery? Which fac tors concerning TNM categories are associated with the possibility of postoperative normalization of calcitonin levels' This study included 64 patients with sporadic MTC operated on from 1986 to 1997. Altogethe r 27 patients underwent primary surgery, and 37 patients were reoperat ed, performing a microdissection of all four locoregional compartments (four-compartment lymphadenectomy, or 4CLA). For primary MTC the bioc hemical cure rate was 100% in node-negative patients and 33% in node-p ositive patients; the latter could be improved to 45% after 4CLA. In c ontrast to reoperative MTC, the rate of lymph node metastases (LNMs) w ith primary MTC correlated with the pT categorS (pT1 33%, pT2 53%, pT3 100%, pT4 100%) but not with age or sex. Again in contrast to reopera tive MTC, mediastinal LNMs in primary MTC were present only in patient s with a pT4 tumor. At reoperation, 4CLA was able to cure 22% of node- positive patients, 28% without proved distant metastases. No patient w ith extrathyroidal tumor involvement or distant metastases was biochem ically cured after either primary or reoperative surgery. For all node -positive MTC patients. in addition to cervicocentral LA at least a bi lateral cervicolateral LA is recommended. Transsternal mediastinal lym ph node dissection is indicated in patients with LNMs in the cervicome diastinal transition, facilitating biochemical cure in up to 45% after the first operation and 22% after reoperative surgery of sporadic MTC .