The key tools for early detection of breast cancer are breast screening and breast self-examination. Breast screening is the regular examination of those who are likely to develop breast cancer, such as mammogram, ultrasound and examination by experienced doctors in regular hospitals. The best time to check your breasts is on the 9th to 11th day after your menstrual period. 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. Breast self-examination techniques are not complicated and can be mastered by the average woman. Breast self-examination techniques include both observation and touch. Breast observation should be done under bright light and in front of a mirror, first of all, to observe whether the bilateral breasts are symmetrical and whether there are any abnormalities; (whether the skin of the breasts is smooth and proportional, whether there are concave and convex changes, whether there are color abnormalities; whether the nipples are sunken or protrude outward). The breast touch requires lying flat on the bed, putting the fingers together and using the palm surface to gently press the opposite breast from the outside to the inside (with the nipple as the center), without forceful grasping or pinching, so as not to damage the normal breast tissue. When touching, first press slowly from the periphery of the breast toward the nipple to see if there are any nodules or lumps; then squeeze from the nipple to the center of the nipple with both hands to see if there is any discharge from the nipple; finally, don’t forget to touch the armpits on both sides to see if there are any enlarged lymph nodes in the armpits. After the observation and touching, you can make a correct judgment on the health condition of your breasts. If you find lumps in the breast, nipple discharge, retraction, erosion, pigmentation, depression or obvious protrusion in the breast, accompanied by enlarged axillary lymph nodes and other symptoms, it is mostly a sign of tumor and you should go to the hospital for a comprehensive examination. It is recommended that women above middle age should have an annual examination in a specialized hospital and a mammogram every two years.