[Cervical lymph node metastasis in medullary thyroid carcinoma].

Objective: To study the patterns of cervical lymph node metastasis of medullary thyroid carcinoma.

Methods: Ninety-one patients with medullary thyroid carcinoma first treated between January 1999 and October 2014 were analyzed retrospectively. Of 91 patients, 39 cases presented with clinical negative node (cN0) and 52 cases with clinical positive node (cN+). Central compartment dissection was performed in all cases. Lateral neck dissection was performed in 52 cN+ cases (71 sides). All neck dissection specimens were obtained and analyzed for lymph node (LN) involvement with respect to neck levels. The distribution of LN with metastasis was studied in cN+ patients and the following factors were used to study the predictive value of central compartment LN metastasis: sex, age, family history, tumor size, bilateral tumor, multifocality of the tumor, extracapsular spread, and remote metastasis. Univariate analysis with the χ(2) test was used to analyze the statistical correlation between central compartment LN metastasis and other clinical factors. Multiple logistic regression analysis was used to identify the factors related to central compartment metastasis.

Results: Neck and bilateral neck metastasis rates were 73.6%, 19.8% respectively. Metastasis rates in central compartment and superior mediastinal region were 68.1% and 27.5% respectively. The central compartment metastasis rate was 33.3% in cN0 patients and 94.2% in cN+ patients. The superior mediastinal metastasis rate was 2.6% in cN0 patients and 46.2% in cN+ patients. Extracapsular spread was an independent predictive factor for central compartment metastasis (χ(2)=15.592, P=0.000, OR=12.876). The incidences of LN metastases at level II, III, IV, V were 62.9%,84.5%,83.1%,50.0% in cN+ patient, respectively. Multi-sites were involved. The possibility of lateral neck metastasis was higher when preoperative value of calcitonin was higher than 300 ng/L (66.7% vs 28.6%, χ(2)=5.771, P=0.016).

Conclusions: Cervical lymph node metastasis of medullary thyroid carcinoma is higher. Central compartment dissection is necessary in cN0 patients with extracapsular spread. Neck dissection from level II to level VII was necessary in cN+ patients. Preoperative value of calcitonin maybe can predict the lateral neck metastasis incidence.