What are the common tests that should be done for early detection of breast cancer?1. Self-examination: (1) Time for breast examination: For women with regular menstrual cycle, the 7th-11th day of menstruation is the best time for breast examination. This is when estrogen has less influence on the breast and the breast is in a relatively quiescent state, making it easy to detect lesions. (2) Self-examination methods: Visual examination: take a sitting or standing position and observe yourself carefully in front of a mirror. First of all, observe the development, shape, size and position of the bilateral mammary glands to see if they are symmetrical and if the nipples are at the same level. Breast development is not exactly the same. Localized elevation is usually one of the local clinical manifestations of the tumor. More superficial lesions sometimes cause localized depression of the skin due to subcutaneous infiltration and traction of the skin. Upward displacement of one breast may be one of the physical signs of breast cancer in the upper half of the breast. Then check the breast skin for redness, varicose veins, rupture, etc., orange peel-like changes and dimple sign. Generally, diffuse redness and swelling are mostly inflammatory changes, while inflammatory breast cancer can also be accompanied by redness and edema of the skin, but it is more common around the areola and under the breast. Finally, check whether both nipples are at the same height and whether there is retraction and depression, epidermal erosion and desquamation. In the case of breast cancer, the nipple is often pulled to the side of the lesion. Inflammatory lesions under the areola or scar contracture after inflammatory lesions, as well as breast cancer can cause nipple retraction. Nipple epidermal erosion and desquamation should exclude nipple Paget’s disease. Palpation: generally in the sitting position, combined with the supine position if necessary. Palpate with the 3 longest fingers flat, using the belly of the finger rather than the tip. From the healthy side to the affected side, lightly press the breast tissue against the chest wall with the finger belly and expand in a spiral clockwise direction from around the areola to the entire breast tissue; or systematically examine the breast in quadrant order, i.e., from the inner upper → inner lower → outer lower → outer upper → areola nipple → axillary lymph nodes. Do not pinch and grasp, so as not to scratch up the gland and cause false sensation. If you find a lump, you should pay attention to its location, size, texture, mobility, the presence of pressure pain and other characteristics, and go to the hospital for further examination in a timely manner. 2.Doctor’s physical examination: Careful examination of all parts of the breast and armpit by an experienced specialist. 3.Ultrasound examination: Ultrasound examination is non-invasive and can be applied repeatedly. It is more valuable for those with dense breast tissue. It can detect lumps and the blood supply around the lumps. The skin is thickened with local echogenic lines, unclear stratification, nipple retraction, and ductal dilatation. 4. Mammography: It can be used as a screening option for people over 40 years old. It is possible to see mass shadows, calcified foci, abnormal blood vessels, translucent ring shadow, thick skin sign, nipple retraction, large duct phase, bull’s-eye sign, tower tip sign, disorder of breast tissue structure, and change in breast morphology.5.Magnetic resonance examination: no radiation damage, three-dimensional imaging, more accurate and sensitive to lesion localization.6.Mammary ductoscopy: suitable for small lesions in the milk ducts with nipple overflow and blood overflow without mass. Using ductal endoscopy technology for visual inspection.7.Puncture biopsy: When a breast lump cannot be determined as benign or malignant, puncture to extract cells or tissues for biopsy and do pathological diagnosis. Ultrasound and mammography are the best combination to make up for each other; for nipple overflow, especially unilateral single-hole hemorrhagic overflow, breast fiber ductal endoscopy should be preferred, but microscopy cannot distinguish benign or malignant lesions, and biopsy is inconvenient or If the lesion is suspected to be located in the terminal ducts and cannot be detected, ductography or mammography should be added; mammography should be used when a tumorigenic occult lesion is considered; MRI should be added when the nodule is difficult to determine benign or malignant.