Initial treatment of differentiated thyroid cancer is aimed at removing the primary tumor, the tissue that has spread outside the thyroid envelope, and the lymph nodes in the affected neck. 2. To reduce the rate of disability associated with treatment and disease. 3.Precise staging of the tumor. 4.Easy to perform iodine-131 internal radiation therapy at the appropriate time after surgery. 5.It is convenient for physicians to precisely monitor the recurrence of the disease in the long term after surgery. 6.It helps to control the risk of recurrence and metastasis of tumor to the minimum. Standard pathological examination shows that 20% to 50% of patients with differentiated thyroid cancer (especially papillary carcinoma) have cervical lymph node involvement, even if the primary tumor is small or confined to the thyroid gland. Postoperative ultrasonography may detect suspicious lymph nodes in the neck in 20% to 31% of patients, and surgical planning may be altered as a result. Accurate staging of the tumor is essential to determine prognosis and guide treatment, however, unlike other tumors, the presence of metastases does not mean that the primary site of differentiated thyroid cancer cannot be removed. Metastatic foci are sensitive to iodine-131 radiotherapy, so even if metastatic foci are present, the primary thyroid tumor and the surrounding tissue that may be involved should be removed during initial treatment. Surgical options for thyroid cancer include: lobectomy near total thyroidectomy [removal of most of the visible thyroid tissue with only a small amount of tissue (about 1 g) attached to the laryngeal recurrent nerve into the cricothyroid muscle area]. Total thyroidectomy (removal of all visible thyroid tissue) – left lobe + right lobe + isthmus. It is worth noting that subtotal thyroidectomy with preservation of the posterior thyroid tissue (>1 g) on the side of the lesion is not suitable for the treatment of thyroid cancer. Subtotal or total thyroidectomy is recommended if: (1) the tumor is >1 cm in diameter; (2) there is a thyroid nodule on the opposite side of the tumor; (3) there is local or distal metastasis; (4) the patient has a history of head and neck radiation therapy; (5) the patient has a first-degree relative with a history of differentiated thyroid cancer. Patients who are older (>45 years old) have a higher recurrence rate and the above mentioned procedures are also recommended. Local lymph node metastasis is present in 20% to 90% of patients with papillary thyroid cancer at the time of diagnosis, while the metastasis rate is lower in patients with other types of tumors. Bilateral central (zone VI) lymph node dissection may improve survival and reduce the rate of lymph node recurrence. In cases where the thyroid lobe is removed due to undiagnosis or the malignant lesion is diagnosed after non-diagnostic biopsy, total thyroidectomy should be performed. In patients with multiple thyroid cancers, total thyroidectomy should be performed to ensure complete excision of the lesion and to prepare for iodine-131 radiotherapy.