OBJECTIVETo study the clinical characteristics, the surgical treatments and the prognostic factors of medullary thyroid carcinoma.

METHODSEighty-two cases of medullary thyroid carcinoma undergoing surgeries between January 1999 and December 2004 were reviewed. There were 39 males and 43 females. Age ranged from 16 to 77 years old, with a median of 46 years old. The calcitonin, chromogranin A and neuron-specific enolase were analysed by immunohistochemistry in samples, and calcitonin was detected in 24 cases. Of them, 28 cases underwent lobectomy with isthmectomy, 24 for remained lobe dissection, 16 for total thyroidectomy, and 14 only for neck and upper mediastinal lymph node dissection. Of the 82 cases, 68 cases underwent trachea esophageal ditch dissection, 53 for unilateral neck dissection, 11 for bilateral neck dissection, 13 for upper mediastinal lymph node dissection through trans-cervical approach, and 5 for mediastinal lymph node dissection through inverted T-shaped incision.

RESULTSImmunohistochemical examination revealed that the expression rates of calcitonin, chromogranin A and neuron-specific enolase were 95.8%, 88.9% and 80.0% respectively. Total metastasis rate of neck lymph nodes was 68.8%, and the rates in level II, III, IV, V and VI were 27.3%, 47.7%, 59.1%, 11.4% and 52.3% respectively. The overall five-year survival rate was 87.8%. The recurrent rate of contralateral lobes was 5.8% and local recurrent rate was 7.3% respectively. Univariate analysis showed that gender, age and TNM stage were significant prognostic factors. Multivariate analysis revealed that distant metastasis was an independent prognostic factor.

CONCLUSIONSStandard radical surgery of the primary and metastatic lesion is key to the treatment of medullary thyroid carcinoma. Lobectomy with isthmectomy should be applied to sporadic medullary thyroid carcinoma, with regular postoperative follow-up, and total thyroidectomy to familial or bilateral medullary thyroid carcinoma. Therefore, detecting the calcitonin is very important for medullary thyroid carcinoma patients' prognosis.