Breast cancer risk factors
Several factors may increase a woman’s risk of breast cancer. Having a risk factor does not mean that you will get breast cancer. Risk factors mean that your risk is higher than a woman of your age with average risk.
Some risk factors cannot be changed, and other risk factors can be changed. Knowing how much each of these factors contribute to breast cancer is difficult. Discuss your own personal risk factors with your clinician to find a strategy for breast cancer screening that is right for you.
Risk factors you cannot change
- Sex: Being a woman is the main risk factor for developing breast cancer. The disease is about 100 times more common in women than in men.
- Age: The risk of developing breast cancer increases with age.
- Family history: Women who have family members with the disease have an increased risk. However, about 85 percent of women diagnosed with breast cancer do not have a family history of the disease. If you have a family history of two or more close relatives with breast or ovarian cancer, a close relative with premenopausal breast cancer, a male relative with breast cancer, or a relative with multiple cancer diagnoses, discuss your family history with your clinician and together you can decide if a consultation with a genetics counselor is right for you.
- Genetic factors: About 5 to 10 percent of breast cancers are thought to be related to an inherited gene mutation that is passed on in the family from parent to child. The most common gene mutations for breast cancer are in the BRCA1 and BRCA2 genes. If you have a family history of one of these gene mutations, or if you have concerns about genetics, your clinician can help you decide if a genetics evaluation is right for you.
- Race and ethnicity: White women are more likely to develop breast cancer, but African American women are more likely to have a more advanced cancer. Women with Ashkenazi Jewish ancestry may have an increased chance of having a BRCA1 or BRCA2 gene mutation.
- Dense breast tissue: Breasts are made up of a mix of fatty, fibrous and glandular tissue. If you have a lot of fibrous or glandular tissue, your breasts are considered dense. Breast density is determined by the radiologist who reads your mammogram. About half of all women have dense breasts. Starting August 1, 2014, Minnesota law requires clinicians to tell women if they have dense breast tissue on their screening mammogram.
Why is breast density important?
Having dense breasts slightly increases your risk of developing breast cancer. Also, dense breasts can make it more difficult for radiologists to find certain types of breast cancer on a mammogram. Park Nicollet uses digital mammography. This technology improves our ability to find breast cancer in dense breasts.
If I have dense breasts, should I still have a mammogram?
Yes. Mammograms are the only imaging test that have been found to decrease deaths caused by breast cancer. Many breast cancers can still be seen even if the breast tissue is dense. We recommend starting yearly mammograms at age 40.
What should I do if I have dense breasts?
You should discuss your overall breast cancer risk with your clinician. Together, you can decide if any additional screening exams are right for you. At this time, experts do not agree if women with dense breasts should have other tests besides screening mammograms. Park Nicollet does offer additional testing for women at increased risk, but these extra tests may lead to further unnecessary testing and biopsies. Also, the extra screening tests might not be covered by insurance. Studies support screening with mammograms and breast MRI in women known to have a very high risk of breast cancer, regardless of their breast density.
- Previous high risk breast biopsy: Women who have previously had a breast biopsy showing atypical cells have a higher risk of developing breast cancer. If you have had an atypical biopsy, discuss those results and any other risk factors with your clinician, and together you can determine a screening strategy that is right for you.
- Menstrual periods: Women who started menstruating before the age of 12 or went through menopause after age 55 have a slightly higher risk of breast cancer.
- Previous chest radiation: Women who have had radiation to the chest area for treatment of another cancer have an increased risk of breast cancer. This risk is highest if the radiation was done before the age of 30. Breast cancer screening should begin five to eight years after finishing treatment, or at age 25, whichever is later. Screening should include mammograms, clinical breast exams and breast MRI.
- Diethylstilbestrol exposure: Some women were given diethylstilbestrol (DES) in the 1940s to 1960s. At the time, DES was thought to lower the risk of miscarriage. These women and their children have a slightly higher risk of breast cancer.
- Personal history of breast cancer: A woman with a personal history of breast cancer has an increased risk of developing a new cancer in the other breast or in a different part of the same breast.
Risk factors you can change
- Having children: Women who have not had children or women who had their first child after the age of 30 have a slightly higher risk of breast cancer.
- Birth control: The data regarding birth control and breast cancer risk is conflicting and no definite increase has been proven. Talk with your clinician when deciding what birth control method is right for you.
- Hormone therapy: Discuss the risks and benefits of hormone replacement therapy for you with your clinician. The data regarding hormone replacement therapy and breast cancer risk is conflicting and no definite increase in risk has been proven.
- Alcohol: Alcohol is linked to an increased risk of breast cancer. The risk is related to the amount of alcohol you consume.
- Obesity: The connection between weight and breast cancer risk is complex, but being overweight after menopause increases your breast cancer risk.
- Lack of physical activity: Research shows that exercise reduces the risk of breast cancer.
Additional information about breast cancer risk factors: