[Predictors of level V lymphatic metastasis in papillary thyroid carcinoma]

To study the predictors of level V metastasis in papillary thyroid carcinoma (PTC).

The clinic data of 122 patients with PTC who underwent therapeutic lateral neck dissection between March 2004 and November 2010 was analyzed retrospectively. There were 31 male and 91 female patients. The median age at diagnosis was 38.5 years (ranging from 8 to 87 years). All the patients had undergone unilateral or bilateral lymph node dissection (II-VI or I-VI). Univariate analysis and multivariate analysis were performed using χ(2) test and binary Logistic regression test, respectively.

The level V metastases was significantly associated with capsular invasion, extrathyroidal extension, preoperative distant metastasis, the size of primary, ipsilateral level IV lymph node metastasis and simultaneous metastases to ipsilateral level II, III and IV (χ(2) = 4.223 - 13.748, P < 0.05). Age, sex, tumor-multifocal, pTNM, central lymph node metastases ipsilateral level II lymph node metastases and ipsilateral level III lymph node metastases were not found to be associated with level V metastases (χ(2) = 0.882 - 3.167, P > 0.05). In multivariate analysis, extrathyroidal extension (OR = 8.32, 95%CI: 2.44 - 28.3, P = 0.001) and simultaneous metastases to ipsilateral level II, III and IV (OR = 7.81, 95%CI: 2.11 - 28.8, P = 0.002) were independent predictors of level V metastasis.

Extrathyroidal extension, simultaneous metastases to ipsilateral level II, III and IV are risk factors for level V lymph nodes metastases in PTC. Dissection of level V lymph nodes should be considered for PTC patients with extrathyroidal extension and simultaneous metastases to ipsilateral level II, III and IV.