Genetic Risk Factors

Hereditary breast cancer accounts for five to ten percent of cases - they are thought to be hereditary, resulting from gene mutations inherited from a parent. These can be inherited from either your mother or father.

BRCA1 and BRCA2
An inherited mutation in the BRCA1 and BRCA2 genes is the most common hereditary risk factor for developing breast cancer. The risk may be as high as 80% for members of some families with BRCA mutations; they are also at an increased risk for ovarian cancer. These cancers tend to occur in younger women and more often affect both breasts than cancers in women who are not born with one of these gene mutations.

These mutations can occur in any racial or ethnic group, however in the United States the BRCA mutations are most often found in Jewish women with Ashkenazi (Eastern Europe) heritage.

Genetic Testing
Genetic testing can be done to look for mutations in the BRCA1 and BRCA2 genes and is covered by most health insurance plans as long as you meet the criteria for testing. It is important that you speak with a genetic counselor, nurse, or physician who is qualified to explain the results of the tests. Although testing may be helpful in some situations, the pros and cons need to be considered carefully.

Family History
Having a first-degree relative (mother, sister, or daughter) with breast cancer almost doubles a woman's risk. Having two first-degree relatives triples her risk.

Personal History
A woman with a personal history of cancer in one breast has an increased risk of developing a new cancer in the other breast or in another part of the same breast. This is called a second primary cancer and is different from a recurrence of the first cancer.

Race and Ethnicity
Statistics show that white women are slightly more likely to develop breast cancer than African-American women, but show that African-American women are more likely to die from breast cancer.

If we look at the statistics by age, we find that breast cancer is more common in women who are under 45 years of age. It is also shown that Asian, Hispanic, and Native American women have a lower risk of developing and dying from breast cancer.

Dense Breast Tissue
Women with denser breast tissue (as seen on a mammogram) have more glandular tissue and less fatty tissue, and have a higher risk of breast cancer. Unfortunately, dense breast tissue can also make it harder for doctors to spot problems on mammograms. If you have dense breasts you should discuss the appropriate imaging studies available to you. The recent introduction of Tomosynthesis technology has shown an improvement in imaging studies for women with dense breasts. Tomosynthesis is available at the Margaret W. Niedland Breast Center. Call (561) 263-4414 to schedule an appointment.

Benign Breast Conditions
Women diagnosed with certain benign breast conditions may have an increased risk of breast cancer. Some of these conditions are more closely linked to breast cancer risk than others.

These conditions show excessive growth of cells in the ducts or lobules of the breast tissue and seem to increase a woman’s risk of breast cancer slightly.
• Usual ductal hyperplasia (without atypia)
• Complex fibroadenoma
• Sclerosing adenosis
• Several papillomas or papillomatosis
• Radial scar

These conditions also show excessive growth of cells in the ducts or lobules of the breast tissue, with some of cells no longer appearing normal. They have a stronger effect on the risk of developing breast cancer.
• Atypical ductal hyperplasia (ADH)
• Atypical lobular hyperplasia (ALH)

Women with a family history of breast cancer and either hyperplasia or atypical hyperplasia have an even higher risk of developing a breast cancer.

Lobular Carcinoma in Situ
Women with lobular carcinoma in situ (LCIS) have a 7 -to 11-fold increased risk of developing cancer in either breast.

Menstrual Periods
Women who started menstruating at an early age (before age 12) and/or went through menopause at a later age (after age 55) causing them to have had more menstrual cycles have a slightly higher risk of breast cancer. The increase in risk may be due to a longer lifetime exposure to the hormones estrogen and progesterone.

Previous Chest Radiation
For women who had radiation as a child or an adolescent as a treatment for cancer have a significantly increased risk for breast cancer. This varies with the age of the patient when they received the radiation. If chemotherapy was also part of the treatment, it may have stopped ovarian hormone production for some time, lowering the risk. The risk of developing breast cancer from chest radiation is highest if the radiation was given during adolescence, when the breasts were still developing. Radiation treatment after age 40 does not seem to increase breast cancer risk.

Diethylstilbestrol (DES) Exposure
The use of DES from the 1940s through the early 1970s for pregnant women to lower their risk of miscarriage has shown a slightly increased risk of developing breast cancer. These women have a slightly increased risk of developing breast cancer. Women whose mothers took DES during pregnancy may also have a slightly higher risk of breast cancer.