Significance of Contralateral Central Lymph Node Dissection in Unilateral cN0 Differentiated Thyroid Carcinoma.

Inclusion Criteria:

* Accurately diagnosing primary differentiated thyroid carcinoma according to pathological diagnostic criteria .

  * Differentiated thyroid carcinoma with cN0(Clinically N0) was diagnosed by thyroid ultrasound text and/or neck CT,and was confirmed with differentiated thyroid carcinoma by postoperative pathological examination.
  * The age is more than 18 years old and less than 65 years old. There is no gender restriction.
  * Untreated patients who have not received surgery, interventional therapy,chemotherapy, biotherapy, and radiation therapy.
  * Physical condition score of Eastern Cooperative Oncology Group（ECOG）: 0-2; no major organ dysfunction; oxygen partial pressure ≥ 10.64 kilopascal（kPa）; white blood cell count≥ 4 × 109/ L; hemoglobin≥ 9.5g/dL; neutrophil absolute count ≥ 1.5 × 109 / L; platelet count ≥ 100× 109 / L; total bilirubin ≤ 1.5 times of the upper limit of normal value;creatinine ≤ 1.25 times of the upper limit of normal value; and creatinine clearance ≥ 60ml / min.
  * Be able to obtain complete follow-up information, understand the situation of this study and sign informed consent.

Exclusion Criteria:

* • ①Bilateral DTC(differentiated thyroid cancer) patients ②Non-DTC(differentiated thyroid cancer)patients ③ Non-cn0(Clinically N0) patients ④ cN0(Clinically N0) patients but could not be operated on.

  * Poorly controlled diabetics (fasting blood glucose levels \> 200 mg/dL). In addition to four types of malignant tumors that can be treated with radical resection, such as cervical cancer in situ, basal or squamous cell skin cancer, (breast) ductal carcinoma in situ, and organ localized prostate cancer, suffering from any other malignant tumors within 5 years.• Breastfeeding and/or pregnant women.
  * Patients with severe bleeding tendencies (prothrombin time less than 50%,cannot be corrected by treatment with vitamin K, etc.).
  * Recent severe hemoptysis, severe cough, dyspnea or patients are not able to cooperate.
  * People with severe emphysema, pulmonary congestion, and pulmonary heart disease.
  * Researchers believe that the subject may not be able to complete this study or may not be able to comply with the requirements of this study (for management reasons or other reasons).