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Genetic Risk Assessment: Assessing Your Risk for Hereditary Cancers
Many factors can affect your personal risk for developing cancer. An estimated 7 percent of breast cancers, 10 percent of ovarian cancers, and 5 percent of colorectal cancers are caused by mutations in genetic information that are passed from generation to generation.
Genetic risk assessment helps identify individuals who are at higher risk for these types of hereditary cancers. A sophisticated blood test gives patients the knowledge they need to make appropriate screening, prevention, and lifestyle management decisions.
Breast and Ovarian Cancers
While every woman should perform regular breast self-exams and have routine mammograms after age 40, there are specific risk factors that indicate the possibility of a BRCA gene mutation:
- Personal or family history of premenopausal breast cancer.
- Personal or family history of ovarian cancer (at any age).
- Personal or family history of male breast cancer.
- Personal or family history of both breast cancer and ovarian cancer.
- Personal or family history of bilateral breast cancer.
- Ethnic background (Ashkenazi Jewish).
If you have any of these risk indicators, talk with your physician about genetic risk assessment.
Why is Risk Assessment Important?
- Mutations in the BRCA genes play a significant role in increasing susceptibility to breast and ovarian cancers.
- Women with a BRCA mutation have an estimated risk as high as 50 percent of developing breast cancer by age 50 and an estimated 56 percent to 87 percent risk by age 70.
- Women with a BRCA mutation have a 27 percent to 44 percent chance of developing ovarian cancer over their lifetimes.
- The chance of a second occurrence of these cancers is also increased.
- Half of all women with a hereditary risk of breast cancer or ovarian cancer inherited the mutated BRCA gene from their father, not their mother.
How Can Risk Assessment Help?
Knowing your BRCA status gives you the opportunity to take steps to reduce your cancer risk.
- The use of oral contraceptives reduces the risk of ovarian cancer.
- Drugs, such as Tamoxifen, have been shown to reduce the risk of breast cancer in high-risk women.
- Your physician may discuss specific strategies such as preventive surgery with you.
- Your physician may recommend increased surveillance, beginning annual mammography and other screening methods as early as ages 25 to 35.
Colorectal and Endometrial Cancers
Hereditary Nonpolyposis Colorectal Cancer (HNPCC) is the most common hereditary colorectal cancer syndrome, responsible for 3 percent to 5 percent of all colorectal cancers and an increased risk for endometrial cancers. HNPCC results from a mutation in the MLH1 and MSH2 genes.
Talk with your physician about genetic risk assessment if you have:
- A personal or family history of colorectal cancer or endometrial cancer diagnosed before age 50.
- A personal or family history of one individual with multiple cancers associated with HNPCC.
- Two immediate relatives with colon or endometrial cancers diagnosed before age 50.
How Can Risk Assessment Help?
- A positive result alerts your physician to begin increased surveillance:
- Colonoscopy every one to three years beginning at ages 20 to 25
- Gynecological screenings for endometrial cancer beginning at ages 25 to 35.
- Several drugs currently are being investigated for prevention of colorectal cancers.
- Your physician may discuss other strategies with you to reduce your cancer risk.
