Breast Cancer
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A risk factor is anything that increases your risk for developing a disease. As medical researchers discover more about the causes of breast cancer, the list of risk factors may change over time.

Having even several of these risk factors doesn't mean you'll get breast cancer. There are different types of risk factors. Some you can't do anything about such as your age, genes and gender. Others like drinking alcohol and watching your weight are risk factors over which you have some measure of control.

If you have concerns about your own risk factors, discuss them with your physician.

Your gender

Being a women is the main risk factor because women’s breast cells are constantly exposed to female hormones, which promote cell growth.  While men can be diagnosed with breast cancer, it is much more common in women.

Your age

Your risk of developing breast cancer increases as you get older. 1 in 8 will be diagnosed with breast cancer in their lifetime. 

Your genes

It is believed that about 5 to 10 percent of breast cancer cases are the result of gene defects inherited from a parent. The most common cause of hereditary breast cancer is an inherited mutation in the BRCA1 and BRCA2 genes. Other gene mutations can also increase your risk of breast cancer, but they are much rarer and don't increase the risk as much as BRCA.

Your family history

Breast cancer risk is higher among women whose close blood relatives (mother, sister, daughter, father, brother) have breast cancer. The American Cancer Society says about 15% of women with breast cancer can have a family member with this disease.  While family history is an important risk factor to know, remember that more than 70% of women who develop breast cancer do not have a family history of the disease.

Personal history of breast cancer

Once you have had breast cancer, you are at an increased risk of developing a new breast cancer.  


Caucasian women are slightly more likely to develop breast cancer than are African American women. African American women tend to have more aggressive tumors and are more likely to die from breast cancer.  Triple negative breast cancer is a prevalent form of breast cancer seen in African American women.

Dense breast tissue

Women with denser breast tissue (as seen on a mammogram) have more glandular tissue and less fatty tissue.  Women with dense breasts have a higher risk of breast cancer. 

Certain precancerous breast conditions

Women diagnosed with certain benign breast conditions may have an increased risk of breast cancer. These changes are often discovered only after you have a breast biopsy for another reason, but they can double your risk of developing breast cancer. Discuss treatment and monitoring options with your doctor.

Previous chest radiation

If you received radiation treatments to your chest as a child or young adult, you are at significantly higher risk to develop breast cancer later in life. The younger you were when you received the treatments, the greater your risk.

Exposure to estrogen

Women who have had more menstrual cycles because they started menstruating before age 12 and/or went through menopause at or after age 55 have a slightly higher risk of breast cancer. The risk is also slightly higher for women who never had children, or whose first pregnancy occurred when they were age 35 or older. This may be related to a higher lifetime exposure to hormones.

Recent oral contraceptive use

Studies have found that women using oral contraceptives (birth control pills) have a slightly greater risk of breast cancer than women who have never used them. Women who stopped using oral contraceptives more than 10 years ago do not appear to have any increased breast cancer risk.

Post-menopausal hormone therapy

Studies have shown a slightly higher risk of breast cancer for women taking the particular combination of hormone therapy — estrogen plus progestin. Discuss the benefits and risks with your doctor.


Use of alcohol is clearly linked to an increased risk of developing breast cancer. The risk increases with the amount of alcohol consumed. The American Cancer Society recommends that women limit their consumption of alcohol to no more than one drink a day

Being overweight or obese

Being overweight or obese increases after menopause is a risk factor for breast cancer. The risk appears to be increased for women who gained weight as an adult but may not be increased among those who have been overweight since childhood. The link between weight and breast cancer risk is complex.

Exposure to certain carcinogens

Chemicals found mainly in cigarette smoke and charred red meat have shown to increase your chances of developing breast cancer. Exposure to certain pesticides also may increase your risk, but more research needs to be done to establish a clear link.

Lack of physical activity

Evidence is growing that physical activity in the form of exercise reduces breast cancer risk. 

Tobacco smoke and secondhand smoke

Heavy smoking may be linked to slightly higher risk in breast cancer.

Researchers are looking into the link between secondhand smoke and breast cancer among women with a family history of breast cancer.