The normal thyroid gland is thin and soft and cannot be seen or felt. If the lump is not painful and isolated, the possibility of thyroid cancer cannot be ruled out. Because there are no obvious symptoms at the beginning of the disease, it is not easy for patients to detect it early, and even if a lump appears, it is often mistaken for other diseases and treatment is delayed. For this reason, our experts remind us that if a lump is found in the neck, we should pay special attention to the shape, size and smoothness of the surface of the lump in order to detect the disease and treat it as early as possible. If the shape of the lump resembles a butterfly, it is usually seen in endemic goiter, thyroiditis and partial hyperthyroidism; if there is a round lump in a part of the thyroid gland, it is usually seen in thyroid cyst and thyroid cancer. 2.Lump size: If the lump is diffusely enlarged or multiple nodular enlargement, it is mostly endemic goiter. However, if the diameter of the cyst is more than 2 cm, thyroid cancer should be suspected. 3. Smoothness and softness of the lump: Touch the surface of the lump carefully with the thumb and index finger, if the surface is smooth, it is mostly endemic goiter; if the surface is not smooth, there is a possibility of goiter. If a single nodule is enlarged and has an unsmooth, solid surface, cancer should be suspected. 4. Growth rate of the lump: endemic goiter grows slowly and has a course of several years; benign tumors and cysts may have a course of several months to several years; while the lump of thyroid cancer grows faster and swells significantly within ten days. 5. Whether lymph nodes are touched: If lymph nodes with hard texture are touched around the thyroid gland, thyroid cancer with local lymph node metastasis should be highly suspected. In addition, prevention of thyroid cancer is not just iodine supplementation. Because, too much iodine intake can also lead to thyroid cancer. In fact, the causative factors of thyroid cancer are not clear and may be related to soil, genetic factors, radiation exposure, etc. Therefore, you should avoid head and neck X-ray irradiation in your life; avoid using estrogen; and avoid fatty and spicy foods. Active treatment of thyroid proliferative diseases and benign tumors can also prevent cancer. It is known that about 20% of single nodules in the thyroid gland are cancerous, 5% of nodular goiter are cancerous, 2% of hyperthyroidism are malignant, and simple goiter still has the possibility of malignant transformation.