The cause of breast cancer is not yet fully understood, but studies have proven that 10%-15% of patients have a family history of breast cancer, and that first-degree relatives with breast cancer are often at high risk, with the risk of developing the disease being 2-3 times higher than that of the general population. Patients with BRCA mutations have a higher chance of having children with breast cancer. Familial breast cancer is rare, but sporadic breast cancer is common. Although breast cancer is genetic, it is not always inherited. There is a debate on whether women with BRCA mutation should undergo preventive mastectomy or be closely monitored. The main preventive measures are as follows: (1) Refuse to be obese: women who have gained weight after menopause or have not applied estrogen replacement therapy are at greater risk of developing the disease. Control the intake of high-fat and high-sugar foods in daily life, and eat more fresh vegetables and vitamin-rich fruits to avoid nutritional overload. (2) Stop bad habits: Epidemiological studies have proven that drinking alcohol twice a day or more than 24g of alcohol per day can increase the risk of breast cancer by about 21%. Therefore, men and women who are alcoholics need to reduce their alcohol intake to reduce the risk of breast cancer. Smoking also significantly increases the incidence of breast cancer. (3) Physical exercise: For thin, child-bearing and premenopausal women, appropriate physical exercise may reduce the risk of breast cancer. (4) Reduce the intake of exogenous estrogen: Avoid hormone replacement therapy as much as possible. (5) Surgery prevention: Some studies have shown that surgery can reduce the risk of the disease by 90% for women with a high-risk family history of the disease. For women with BRCA1 and BRCA2 mutations, total mastectomy to reduce the risk is an option, but not recommended. (6) Regular medical checkups: Regular self-testing is recommended, and for women aged 40 years and older, annual medical checkups should be performed. At present, primary prevention is most important because the cause of breast cancer is not yet clear. Early detection and treatment is the key to improve the prognosis of breast cancer.