If the microscopic thyroid cancer has been observed for five years and there is no significant change in tumor diameter and nature within five years, patients may choose to continue observation and treatment and do not necessarily need surgery. Microscopic thyroid cancer refers to thyroid cancer with a tumor diameter of 10mm or less, also known as occult thyroid cancer. Microscopic thyroid cancer usually progresses slowly, has low malignancy and has a very good prognosis with a five-year survival rate of 97%. If there is no significant change in microscopic cancer after long-term follow-up, it can be closely observed temporarily and not surgically removed. However, microscopic thyroid cancer is not equal to low-risk cancer. Clinically, although some microscopic thyroid cancer is small, not more than 10mm, lymph node metastasis or distant metastasis has already occurred, and a small number of microscopic thyroid cancer progresses rapidly, and about 5% of them will develop into poor prognosis of poorly differentiated cancer or even undifferentiated cancer. Therefore, once the diagnosis of microscopic thyroid cancer is confirmed, unless the patient cannot tolerate surgery due to old age, many comorbidities or other reasons, or cannot be operated, surgery is usually recommended to remove the thyroid gland in order to eliminate future problems.