1. Female breast: it is composed of skin, fibrous tissue, breast glands and fat. Breast cancer is a malignant tumor that occurs in the epithelial tissue of the breast gland. 99% of breast cancer occurs in women and only 1% in men.

2. Global breast cancer incidence rate: in 2020, there were 2.26 million new breast cancer patients in the world, and breast cancer replaced lung cancer as the largest cancer in the world. There are 416000 new cases of breast cancer in China, which has become the first malignant tumor in women.

3. Breast cancer has become a major public health problem. Since the 1990s, the global mortality rate of breast cancer has shown a downward trend; The reasons are: first, the development of breast cancer screening has increased the proportion of early cases; Second, the development of comprehensive treatment of breast cancer has improved the curative effect. Breast cancer has become one of the most effective solid tumors.

4. Age of female breast cancer: the incidence rate of breast cancer is lower in the age group of 0-24 years old, and gradually increases after 25 years old, reaches the peak in the group of 50-54 years old, and gradually decreases after 55 years old.

5. The patients with nipple discharge as the primary symptom accounted for about 10% of breast diseases, and the incidence rate was second only to breast lump and breast pain. Nipple discharge mostly occurs in mammary hyperplasia, intraductal papilloma, breast inflammation, mammary duct ectasia or breast cancer. Bloody nipple discharge often occurs in intraductal papilloma or breast cancer.

2020 Statistics of new incidence rate of cancer in Chinese women