Early symptoms of breast cancer are usually not obvious. It is manifested as a lump in the breast, painless single small lump, the lump is usually found unintentionally or discovered during physical examination, the lump is hard, the surface is usually not smooth, the demarcation with the surrounding tissues is not very clear, the mobility in the breast is poor, usually not easy to be pushed, with the enlargement of the lump, a localized bulge in the breast can appear. If the mass encroaches on the ligaments of the breast, the dimple sign, which is a depression of the skin on the surface of this mass, may appear. If the mass in the critical tissue and areola is shortened due to invasion of milk ducts, the nipple can be pulled to the side of the cancer, which makes the nipple flat, concave or retracted, and this kind of mass is very easy to increase in rate, and it can invade the subcutaneous lymphatic ducts, and there is an orange-peel-like change, which is dermal edema. Once breast cancer has progressed to an intermediate or advanced stage, it may invade the pectoral fascia and pectoral muscles to the extent that the mass fixes the chest wall and cannot be easily pushed. There is a possibility of skin invasion leading to the formation of ulcers on the skin. If breast cancer metastasizes to the axillary lymph nodes, there may be enlarged axillary lymph nodes, which are usually hard in texture, without much pain, and may be fused with each other with the prolongation of time, and may even adhere to the skin and deep tissues. Breast cancer may also have distant metastasis. If lung metastasis occurs, chest pain, chest tightness and shortness of breath may appear; if bone metastasis occurs, localized pain in the bone may appear; if liver metastasis occurs, hepatomegaly or jaundice may appear and other symptoms. The key to breast cancer is early detection, timely intervention and timely treatment, and the prognosis is still relatively good.