This study is a phase III, randomized controlled, open label non inferiority study. Patients who meet the inclusion criteria are randomly assigned 1:1 to either the experimental group (selective neck dissection) or the control group (modified neck dissection), with LRFS as the primary endpoint. The aim of the study is to evaluate the safety of selective neck dissection in papillary carcinoma with limited number of lymph node metastases in the lateral neck, and the quality of life compared with modified neck dissection.

Inclusion Criteria:

• Pathologically confirmed PTC;
• Age range: 14-80 years old;
• Preoperative fine needle aspiration confirms lymph node metastasis in the lateral neck
• Ultrasound and CT suggest that metastatic/suspected metastatic lymph nodes are limited to compartment IV, with 1-2 lymph node metastases and <1cm in short diameter. The lymph nodes have no central necrosis, liquefaction, peripheral enhancement, or disappearance of adjacent fat spaces (predicting unobstructed lymphatic vessels);
• Thyroid tumors without extra thyroidal extension;
• Enough thyroid volume to inject tracer.

Exclusion Criteria:

• Previous neck surgery;
• Bilateral neck lymph node dissection;
• Distant metastases;
• High risk pathological subtypes or the presence of other high-risk factors for recurrence;
• Previous treatment for thyroid cancer other than endocrine therapy;
• The patient is unable to cooperate with follow-up.