Preoperation risk of CLNM is important for deciding extent of surgery.
The association between TSH and CLNM was only observed by few of studies [3, 27].
An evaluation based on the predictive risk factors is more effective than the one based on US features of cervical lymph nodes to predict the CLNM in PTC patients.
In conclusion, our study explored and confirmed the impact of gender on the predictive risk factors of CLNM in PTC for the first time.
Therefore, it is important to identify the risk factors associated with CLNM in specific PTC, which may assist surgeons in making the decision whether to perform selective pCND.
 reported that 33.3% of patients with CPTC were found to have CLNM. In this study, the incidence of CLNM in patients with [cN.sub.0] CPTC was 63.2%.
 reported that ages younger than 45 years were an independent predictor of the presence of CLNM, which allowed for selective pCND in PTC.
Previous studies have shown that larger tumor size was the risk factor for the presence of CLNM in patients with PTC [28-30].
The relationship between tumor bilaterality and CLNM in patients with PTC is still controversial.
The second limitation was that we could not evaluate the effect of occult CLNM identified by pCND on oncological outcomes of patients with [cN.sub.0] CPTC, because the follow-up time was relatively short in this study.
Ages <45 years, tumor size >2 cm, and bilaterality are independent risk factors of CLNM, which allow for selective CND in patients with [cN.sub.0] CPTC.