In recent years, many patients have come to the hospital with thyroid nodules during physical examinations or have been found to have thyroid nodules, and it has been found clinically that the number of patients with thyroid nodules is increasing year by year. It has been documented that the incidence of thyroid nodules ranges from 25-70% in women and 10-50% in men. When screening the immediate population with high-resolution ultrasound, the detection rate of thyroid nodules is 19-67%. As the incidence of thyroid nodules increases, the incidence of thyroid cancer also increases significantly, with the incidence of thyroid cancer in thyroid nodules ranging from 5-15%. The incidence of thyroid cancer in the United States has increased from 3.6 cases per 100,000 people in 1973 to 8.7 cases per 100,000 people in 2002 and is still increasing in recent years. In Japan and Korea, the incidence of thyroid cancer is the first among women and has surpassed that of breast cancer. Some scholars have suggested that this phenomenon may be due to improved screening and detection tools that can detect patients at an early stage (e.g., ultrasound for early diagnosis of small nodules). However, recent reports suggest that the incidence of thyroid cancer is indeed increasing and is not solely due to improved early screening and detection, but may be related to radiation, genetics, diet, and environmental pollution. The vast majority of thyroid nodules are benign, with only a very small number of cystic nodules and some solid nodules being thyroid cancer. Most of the thyroid cancers are well-differentiated and less malignant tumors, which are also called differentiated thyroid cancers, and papillary thyroid carcinoma is the main pathological type, and some of them are follicular thyroid carcinoma. Differentiated thyroid cancer is usually a single solid nodule that grows relatively slowly and does not cause significant discomfort to the patient. The survival period of patients with differentiated thyroid cancer is longer than that of other malignant tumors. Generally, after surgical removal of the tumor, the survival period of patients with no obvious metastasis is more than 10 years, which means that after treatment by regular professional thyroid surgeons, the survival rate of 10 years is more than 95% and basically cured. Differentiated thyroid cancer is difficult to distinguish benign from malignant before surgery, and the final result relies on pathological examination. The most commonly used diagnostic methods are thyroid ultrasound, radionuclide pro-tumor imaging and thyroid aspiration, and the internationally accepted method is FNA, which is a fine needle aspiration of the thyroid gland, and has the following signs: (1) sandy calcification; (2) hypoechoic nodules; (3) abundant blood supply; (4) irregular boundary and surrounding invasion; (5) anterior-posterior cross-sectional diameter greater than the left-right diameter. If there are three or more of these signs, thyroid cancer should be highly suspected, especially if there are sand-like calcifications. Radionuclide pro-tumor imaging of thyroid cancer often shows “cold nodules” on static thyroid imaging, and after injection of pro-tumor imaging drugs, the “cold nodules” appear to be obviously filled. This suggests that the tumor cells are actively proliferating and are suspected to be malignant. 80% of large calcifications found on ultrasound examination of the thyroid gland are benign lesions, while most small calcifications, especially sand-like calcifications, are malignant tumors. In the clinic, many patients with ultrasound reports from physical examinations ask whether a nodule of a few millimeters in diameter needs to be treated. There is no uniform standard in China, but most doctors in hospitals believe that nodules over 1.5-2 cm in diameter need to be surgically removed. In my opinion, thyroid nodules should not focus too much on size, but rather on the content of the mass, such as the presence of calcification, echogenicity and blood flow, etc. Benign lesions can be observed on a follow-up basis, while surgery should be considered when cancer is suspected. Surgery is currently the best treatment for thyroid nodules. In some patients, levothyroxine has some inhibitory effect on the growth of thyroid nodules when they are small in size, but it is not statistically significant. Levothyroxine indirectly inhibits tumor growth by suppressing thyrotropic hormones secreted by the pituitary gland, but it is not effective in areas with adequate dietary iodine.