The absence of cancer embolus and invasion of thyroid isthmus cancer suggests that thyroid cancer has not metastasized and local invasion, which indicates that thyroid cancer is still in the early stage and has a better prognosis. The severity of thyroid cancer mainly depends on the pathological type of tumor, tumor diameter, the extent of tumor invasion, the presence or absence of lymph node metastasis, and the presence or absence of distant metastasis. Thrombus is the accumulation of cancer cells in blood vessels or lymphatic vessels, and the absence of thrombus often suggests that thyroid cancer has not metastasized to distant places. The absence of local invasion also suggests that the thyroid cancer is confined to the thyroid gland. However, it should be noted that the type of pathology is also an important factor in determining the condition of thyroid cancer. The degree of malignancy varies greatly among different types of pathology, and the higher the degree of malignancy, the worse the prognosis. The severity of the patient’s condition should be comprehensively judged by professional doctors, and accordingly the best treatment plan should be formulated, with the patient’s active cooperation, in order to harvest the best prognosis.