Breast cancer is most commonly seen in the outer upper quadrant of the breast (40-50), followed by the nipple areola (15-20) and the inner upper quadrant (12-15). The main symptoms and signs are as follows:1 Lumps in the breast Most of the breast cancer patients discover their lumps in the breast unintentionally, so lumps can be considered as the first symptom of breast cancer. The earliest manifestation is a small, painless, solitary lump in the affected breast. The lump is hard, not smooth on the surface, not clearly demarcated from the surrounding tissues, and not easily pushed inside the breast. Therefore, any woman over 45 years old who finds a painless lump in the breast by chance should be highly alerted and the first thing to think of is the possibility of breast cancer. Zhang Chenguang, Breast Surgery Department of Xinjiang Cancer Hospital, clinically failed to palpate the lump in the breast, but the disease has developed to axillary lymph node metastasis or visceral metastasis is called occult breast cancer. The primary lesion of this kind of occult breast cancer is extremely small, sometimes only 1~2mm, usually without clinical signs, and often found during physical examination.2 Breast pain Generally speaking, pain is not a common symptom of breast cancer, most women have physiological breast pain, but of course, postmenopausal women who do have obvious breast pain should also consider the possibility of breast cancer.3 Nipple overflow, which is bloody, purulent or plasma in nature, is mostly suggestive of breast cancer. This is usually a benign lesion, not a sign of breast cancer. Bloody nipple discharge is mostly seen in intraductal papilloma, but malignant change of intraductal papilloma or intraductal papilloma cannot be excluded.4 Changes in nipple and breast skin (1) Adhesion and indentation of skin or nipple Clinically, cancer mass grows faster, and as its volume increases, invasion of surrounding tissues may cause changes in breast shape. As the growth of cancer cells stimulates the proliferation of fibrous tissue in breast tissue, not only does the lump become hard, but also the cancer lump invades Cooper’s ligament, which connects the gland with the skin, and the fibers of Cooper’s ligament contract, causing the skin on the surface of the lump to sink. The cancer mass adjacent to the nipple may draw the nipple in the direction of the lesion because it invades the milk duct and makes it contract, and the cancer mass deep in the nipple also makes the nipple sunken because it invades the milk duct. These are important signs of breast cancer. (2) Skin edema and orange peel-like changes As the cancer mass continues to grow, the skin on the surface may be blocked by cancer cells in the intra- and subcutaneous lymphatic vessels, resulting in local lymphedema. Since the skin is closely adhered to the subcutaneous tissue at the hair follicle, many dotted depressions can be seen at the hair follicle when the lymphedema is present, forming the so-called orange peel-like changes. (3) Breast wrinkling and fixation When breast cancer develops to advanced stage, it may invade the pectoral fascia and pectoral muscle to the extent that the cancer mass is fixed in the chest wall and cannot be pushed. If the cancer cells spread widely to the skin of the breast and the skin around the breast, many hard nodules or small cords will occur; the small nodules or cords will connect with each other and fuse to form a dark red, diffuse patch, or even spread to the skin of the back and the opposite side of the chest, forming the so-called armored carcinoma, which will tighten the thorax and cause difficulty in breathing. Sometimes the skin may break down and form an ulcer, which often has a foul odor and bleeds easily, and sometimes turns out to be cauliflower-like. The supraclavicular lymph nodes are also enlarged and hardened, and there are also lymph node metastases in the opposite axilla. If the cancer cells block the main lymphatic vessels in the axilla and cause obstruction of lymphatic flow in that side of the arm, a waxy white arm edema will occur. If a hard lymph node in the subclavian or axillary area compresses the axillary vein, bruising edema will occur in the arm on that side. If the nerve trunk is invaded by the cancer or compressed by the stiff lymph node, it will cause severe pain in the arm and shoulder. The metastasis of lung and pleura often causes cough and dyspnea; the metastasis of liver can cause hepatomegaly and gangrene. Finally, cachexia will occur, and the patient will be weak, anemic, feverish, and even die. The duration of untreated breast cancer varies, with an average of 38-40 months. According to the different degrees of breast cancer development, breast cancer is clinically divided into four stages in China. This staging is more practical and extremely important for the formulation of treatment plans. Stage I: The cancer is completely located in the breast tissue. The diameter does not exceed 3cm and there is no adhesion with the skin. There is no axillary lymph node metastasis. Stage II: The cancer is not more than 5 cm in diameter, still movable, and adherent to the skin. There are several scattered and movable lymph nodes in the ipsilateral axilla. Stage III: The cancer tumor is more than 5 cm in diameter, with extensive adhesions to the skin and often forming ulcers; or the base of the cancer tumor has adhesions to the fascia and pectoral muscle. There is a series of fused lymph nodes in the ipsilateral axilla, but they can still move. Those with metastatic lymph nodes next to the sternum also belong to this stage. Stage 4: The cancer spreads widely to the skin or is fixed to the chest muscle or chest wall. The lymph node mass in the ipsilateral axilla has been fixed, or shows extensive lymph node metastasis (supraclavicular or contralateral axilla). It is often accompanied by distant metastasis.