Materials and Methods

From September 2014 to February 2015, a total of 321 PTC patients were enrolled retrospectively. Except for 154 N0 patients, the remaining 167 patients were divided into two groups as follows: Group I (n= 140), central lymph node (LN) metastasis (pN1a); Group II (n= 27), lateral LN metastasis (pN1b, n= 23) or LN recurrence (n= 4). The patients who had LN metastasis or recurrence underwent selective LN dissection or recurrent LN excision.

Results

Central LN metastases were found in 44.0%(142/321) of patients. Two hundred thirty patients (71.7%) were classified as being at low-risk for LN disease, as evidenced by N0 or fewer than five micrometastases. The mean size of central metastatic LNs was 0.37±0.34 cm. A total of 76 patients (46.6%) presented with micrometastasis, and ten (3.1%) presented with extranodal extension (ENE). The multiple/bilateral cancer, Extrathyroidal extension, size of metastatic LN, ENE, high risk LN disease (> 5, macrometastasis,> 3.0 cm) and high thyroglobulin were significant risk factors in predicting LN recurrence or lateral LN metastasis (p< 0.05) in univariate analysis. Patients with ENE were 10.3 times more at risk for recurrence or metastasis than patients without ENE.

Conclusion

We consider the ENE was the most potent risk factors for LN recurrence or lateral LN metastasis in PTC.