First of all, what are the causes of nipple invagination: the first cause is congenital, caused by nipple invagination after birth, which is mostly due to the poor development of the milk ducts, causing nipple invagination. The second cause of nipple invagination is acquired, including surgery or inflammation. The third one is disease, the most important disease is breast cancer. The main reason why breast cancer causes nipple invagination is that breast cancer invades the milk duct behind the nipple and causes shortening of the milk duct, which causes nipple invagination. What is the difference between nipple invagination caused by breast cancer and other forms of nipple invagination? It is congenital and usually occurs from birth, while breast cancer invagination usually occurs later. Another important difference from surgically induced nipple invagination is that it may have a history of surgery, whereas breast cancer nipple invagination usually occurs suddenly without any medical history of nipple retraction. Another important difference between breast cancer and nipple invagination is that it may have a history of surgery, whereas breast cancer may have no history of nipple invagination and sudden nipple retraction. The first treatment for nipple invagination caused by breast cancer is to go to the hospital for further treatment as soon as possible.