Papillary thyroid cancer (PTC) is the most frequent subtype among thyroid cancers. Lymph node (LN) metastases are frequent in PTC and the incidence is 60% on average. Recent studies have shown that there has been an increase in the mortality or recurrence with LN metastases and that more than 5 metastatic LNs are clinically important. Therefore, we investigated clinicopathologic factors associated with clinically important LN metastases.

From January 2010 to October 2013, we retrospectively enrolled 2,628 PTC patients who underwent thyroidectomy at Ajou University Hospital. Among 1,425 patients with LN metastasis, 325 had ≥ 5 LN metastases.

In univariate analysis, young age (< 45 year), male gender, capsular invasion, multiplicity, tumor size, and lymphovascular invasion (p < 0.001) were statistically associated with both LN metastasis and ≥ 5 LN metastases. However, Braking Action Fair (BRAF) mutation was not important to predict LN metastasis (p > 0.05). In multivariate analysis, lymphovascular invasion was the most important factor (odds ratio: 4.7, 4.0) among other clinicopathologic factors (odds ratio:< 2.1).

Braking Action Fair (BRAF) mutation was not useful to predict the LN metastasis. However, lymphovascular invasion was the most important factor to predict more than five cervical LN metastasis which is very important clinically.