Breast cancer is a common gynecological disease, and in recent years, many media and experts have been calling on women to pay attention to breast cancer prevention, and they think that the best way to prevent it is to go to a hospital for a specialist examination. So how old should women be when they start to have checkups? When is it too early to have a checkup to prevent breast cancer? Some doctors suggest 40 years old, some say 30 years old, but it should be 20 years old. It is important for women to pay attention to and shelter their breasts from the age of 20, self-examining them once a month and going to the hospital for breast examination once every three years. 40-50 years old should be examined every one or two years, and women over 50 years old should have a breast health examination once a year, and those who have benign breast diseases should be examined once every six months. Oncology experts believe that it is impossible for cells in the human body to change from normal state to cancer cells at once, and there is a gradual process from quantitative to qualitative change between them, which may take 5 to 10 years. If you can find the cancer cells in their budding state, you may only need a minor surgery; you can still inherit your past life, as the cure rate of early stage breast cancer is over 90%. On the other hand, most of the patients with middle and late stage breast cancer not only lose their fair breasts, but also their incomparable lives. Medical experts and the media used to exaggerate that women should perform self-examination of their breasts, but the US guidelines for early cancer diagnosis in 2005 no longer recommend regular breast self-examination as an early diagnosis method for breast cancer. This is not to deny the importance of self-examination of the breast, but the pivotal issue is that most patients do not grasp the “self-examination technique”, resulting in many tumors that cannot be felt at all. In addition, breast self-examination can only detect tumors that are large to a certain extent, but there is nothing that can be done for small lesions, especially those in the budding state. Ultrasound and X-ray are the most routine screening methods for breast cancer diagnosis, but ultrasound is more suitable for young women under 40 years old. The breast glands of young women are generally denser. When X-ray imaging, the dense glands may obscure some tissues, including tumor tissues, which can easily miss the microscopic lesions.