What are the causes of breast cancer

What are the causes of breast cancer-what ages can get a breast cancer??Risk factors 

A risk factor is something that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, such as smoking, drinking, and diet are linked to things a person does. Others, like a person's age, race, or family history, can't be changed. 

But risk factors don't tell us everything. Having a risk factor, or even several, doesn't mean that a woman will get breast cancer. Some women who have one or more risk factors never get the disease. And most women who do get breast cancer don't have any risk factors. Some risk factors have a greater impact than others, and your risk for breast cancer can change over time, due to factors such as aging or lifestyle. 

Although many risk factors may increase your chance of having breast cancer, it is not yet known just how some of these risk factors cause cells to become cancer. Hormones seem to play a role in many cases of breast cancer, but just how this happens is not fully understood. 

Risk factors you cannot change 

Gender: Being a woman is the main risk for breast cancer. While men also get the disease, it is about 100 times more common in women than in men. 

Age: The chance of getting breast cancer goes up as a woman gets older. About 2 out of 3 women with invasive breast cancer are 55 or older when the cancer is found. 

Genetic risk factors: About 5% to 10% of breast cancers are thought to be linked to inherited changes (mutations) in certain genes. The most common gene changes are those of the BRCA1 and BRCA2 genes. Women with these gene changes have up to an 80% chance of getting breast cancer during their lifetimes. Other gene changes may raise breast cancer risk, too. 

Family history: Breast cancer risk is higher among women whose close blood relatives have this disease. The relatives can be from either the mother's or father's side of the family. Having a mother, sister, or daughter with breast cancer about doubles a woman's risk. (It's important to note that 70% to 80% of women who get breast cancer do not have a family history of this disease.) 

Personal history of breast cancer: A woman with cancer in one breast has a greater chance of getting a new cancer in the other breast or in another part of the same breast. This is different from a return of the first cancer (called recurrence). 

Race: White women are slightly more likely to get breast cancer than African-American women. But African American women are more likely to die of breast cancer. At least part of the reason seems to be because African-American women have faster growing tumors, but we don't know why this is the case. Asian, Hispanic, and Native-American women have a lower risk of getting and dying from breast cancer. 

Dense breast tissue: Dense breast tissue means there is more gland tissue and less fatty tissue. Women with denser breast tissue have a higher risk of breast cancer. Dense breast tissue can also make it harder for doctors to spot problems on mammograms. 

Certain benign (not cancer) breast problems: Women who have certain benign breast changes may have an increased risk of breast cancer. Some of these are more closely linked to breast cancer risk than others. For more details about these, see our document, Non-cancerous Breast Conditions. 

Lobular carcinoma in situ: Women with lobular carcinoma in situ (LCIS) have a 7 to 11 times greater risk of developing cancer in either breast. 

Menstrual periods: Women who began having periods early (before age 12) or who went through the change of life (menopause) after the age of 55 have a slightly increased risk of breast cancer. They have had more menstrual periods and as a result have been exposed to more of the hormones estrogen and progesterone. 

Earlier breast radiation: Women who have had radiation treatment to the chest area (as treatment for another cancer) earlier in life have a greatly increased risk of breast cancer. The risk varies with the patient's age when they had radiation. The risk from chest radiation is highest if the radiation were given during the teens, when the breasts were still developing. Radiation treatment after age 40 does not seem to increase breast cancer risk. 

Treatment with DES: In the past, some pregnant women were given the drug DES (diethylstilbestrol) because it was thought to lower their chances of losing the baby (miscarriage). Recent studies have shown that these women (and their daughters who were exposed to DES while in the womb), have a slightly increased risk of getting breast cancer. For more information on DES see our document, DES Exposure: Questions and Answers. 

Breast cancer risk and lifestyle choices 

Not having children or having them later in life: Women who have not had children, or who had their first child after age 30, have a slightly higher risk of breast