What causes breast cancer?

The occurrence of breast cancer can cause great harm to the patient's body. For some preventable causes, we can take preventive measures. Menstruation, age, genetics and other factors may affect the occurrence of breast cancer.

The causes of breast cancer are as follows:

1. Genetic factors: Studies have found that women with first-degree relatives suffering from breast cancer have a 2-3 times higher risk of developing breast cancer than those with no family history. If a first-degree relative suffers from premenopausal or postmenopausal bilateral breast cancer, the relative risk of breast cancer herself is 9 times and 5 times higher, respectively. About 5% to 10% of breast cancers are caused by certain genetic gene mutations. Mutations in the p53, BRCA1 and BRCA2 genes are closely related to the occurrence of breast cancer.

2. Age factor: For the general population, the severity of breast cancer incidence and mortality increases with age. The severity of breast cancer at the age of 70 is three times that of 40, and the annual mortality rate of breast cancer at the age of 70 is five times that of 40. The risk of a 50-year-old woman being diagnosed with breast cancer in the next 10 years is 1 in 40; for a 70-year-old woman it is 1 in 25; and for a 90-year-old woman it is 1 in 8. However, because the number of elderly women dying from other causes gradually increases, the mortality rate from breast cancer does not increase significantly after the age of 65.

3. History of breast disease: Data show that some non-proliferative benign breast diseases, such as mastitis, breast duct ectasia, breast cysts and breast fibroma, have a lower chance of becoming cancerous, but at the same time they are also related to breast cancer. In addition, there are some proliferative breast diseases that greatly increase the risk of breast cancer, especially those accompanied by atypical lobular or ductal hyperplasia.

4. Pregnancy and lactation history: Pregnancy and lactation history is also one of the risk factors of breast cancer. Early age of first birth can reduce the risk of breast cancer, and full-term pregnancy is a necessary condition for the protection of breast cancer. While breastfeeding duration is not a factor that directly affects breast cancer, experts believe that breastfeeding for 5 years can reduce the risk of breast cancer by 30%. Some people also believe that a long breastfeeding period is a simple manifestation of frequent parity. After considering the effect of parity, the effect of breastfeeding disappears.

5. Menstrual history: Early menarche is one of the important factors in the development of breast cancer. Women whose menarche occurs before the age of 12 are more than four times more likely to develop breast cancer than those who occur after the age of 13. It is generally believed that if the age of menarche is delayed by one year, the risk of breast cancer will be reduced by 20%. At the same time, delayed menopause will increase the risk of breast cancer.