Although breast cancer is not the cancer that causes the most deaths in women, it is one of the most prevalent cancers in women. Early detection of breast cancer is especially important to reduce mortality and improve the quality of survival. Therefore, breast self-examination and breast screening are the most important things we need to adhere to. I. The three breast self-examination methods recommended by the American Cancer Society are: 1. Self-examination in the mirror First face the mirror, cross your arms and observe the shape of your breasts. Then raise your arms above your head and carefully observe whether there is any change in the shape and outline of both breasts; whether there is any redness, rash, superficial venous anger, skin folds, orange peel-like changes and other abnormalities in the skin of the breasts; whether the nipples are at the same level, whether there is elevation, retraction, depression, whether there is any abnormal discharge from the nipples and whether there is any change in the color of the areola. Finally, put down both arms, cross the waist with both elbows and try to backward, so that the chest muscles are tense, and observe whether both breasts are equal and symmetrical, and whether there are any abnormalities in the nipples, areolas and skin. 2, lying touch method First take the supine position, the right arm raised above the head, and a small pillow under the right shoulder, so that the right breast flat. Then put the four fingers of the left hand together and use the palm of the fingertips to check whether there are lumps or other changes in various parts of the breast. There are three methods of examination: one is the clockwise circular examination method, in which four fingers are used to examine the breast from the nipple area in a circular fashion from the inside out. The second is the vertical belt examination method, in which the four fingers are used to examine the entire breast from top to bottom. The third is the wedge examination method, in which the four fingers are used to examine the breast in a radial pattern from the nipple outward. The left breast is then examined in the same way, and the two breasts are compared for differences. Finally, use your thumb and index finger to gently squeeze the nipple, if there is a clear or bloody discharge should be reported to the doctor. 3, shower inspection method shower, because the skin is wet easier to find breast problems. The method is to slowly slide the palm of one finger and carefully examine all parts of the breast and the armpit for lumps. Breast examinations should be done frequently. The best time for breast self-examination is usually the 9th to 11th day after the onset of menstruation. This is when estrogen has the least effect on the breast and the breast is in a relatively static state, making it easy to detect lesions. Also note that bras should be worn properly, too tight, too thick, poor ventilation, will affect the normal circulation of lymphatic fluid in the breast, can not remove harmful substances in a timely manner, over time, easy to make breast cell lesions. There is no need to be nervous when self-examination reveals breast hyperplasia, because breast hyperplasia is not equal to pre-cancer, but we should not be paralyzed and should still insist on frequent self-examination. If there are cystic hyperplasia, lumps or nodules, they may develop into breast cancer, therefore, although the incidence is not high, they should be treated as soon as possible. Second, how can we identify breast lumps as signs of cancer? First of all, pay attention to the symmetry of bilateral breasts, if the symmetrical parts of both breasts can be touched, such as thickened lumps and so-called “swellings”, it is usually a physiological phenomenon; secondly, pay attention to the relationship between breast changes and menstrual period, if the so-called “swellings” appear in the breasts before menstruation, but can disappear after menstruation. If the so-called “swelling” appears in the breast before menstruation and can disappear after menstruation, then it may also be a physiological phenomenon. Once again it is a before-and-after comparison, i.e. if something that was not in the breast before is now felt, be extra careful. Of course, if the nipple is running and sunken, it is even more important to see a breast specialist. In conclusion, the earlier suspicious lesions in the breast usually require instruments such as mammography and ultrasound to further clarify whether it is a tumor or not. In addition, more than 90% of people come to the doctor because of breast pain, only 3-5% are breast cancer. Therefore, breast cancer is usually a painless tumor. Of course, the best way to detect and prevent breast cancer at an early stage is to attend regular breast screening, i.e., breast ultrasound and mammogram (mammogram), and the final diagnosis must be confirmed by biopsy (pathological examination) before a definite conclusion can be made. The significance of breast screening is: early detection of breast cancer and intervention to reduce mortality. If breast cancer can be detected at stage 0, it may only require a minimally invasive surgery to eliminate the hidden tumor. In summary, with good breast self-examination and breast screening, the mortality rate of breast cancer can be greatly reduced and the quality of long-term survival can be improved.