After a long period of practice and scientific research, the following factors may be high risk factors for breast cancer: (1) Age, menstruation, childbirth, breastfeeding, living environment and economic status Breast cancer is more common in middle-aged and elderly people. Early menarche (menstruation before age 12), late menopause (menopause after age 50-55), first childbirth after age 35 or never having children, or having children without breastfeeding may all have an impact on the occurrence of breast cancer. And the incidence of breast cancer is relatively higher in urban than rural areas, especially among those with more privileged socio-economic status. (2) History of breast disease and benign tumor surgery Some women had minor breast surgery due to certain breast diseases or benign tumors. The surgery inevitably cuts off some breast ducts, making the distal ducts not open. The accumulation of secretions in the ducts may lead to cancer if they stimulate the breast tissue for a long time. However, do not reject some breast diseases that must be treated surgically, such as cystic lobular hyperplasia and intraductal papilloma, which may become cancerous in the future if not removed surgically. Surgery is still necessary, but post-operative follow-up examinations should be conducted frequently for timely detection, diagnosis and treatment. In addition, patients with breast cancer on one side have an increased chance of developing breast cancer on the opposite side, so it is important to pay attention to whether there is a lump in the opposite breast after breast cancer surgery. (3) X-rays of the breast Smaller doses of X-rays will not cause breast cancer, but many patients are eager for treatment and have multiple mammograms in several hospitals within a short period of time, especially young women, which increases the risk factor of breast cancer. However, patients do not have to worry about the risk of breast cancer from X-ray. Because the radiation dose of mammography is very small, it is not cancer-causing. (4) Family aggregation and hereditary factors Women who have immediate family members with breast cancer have a higher risk of having breast cancer. It is thought that this is related to genetic factors. Therefore, if someone in the family has breast cancer, other members should be more alert.