Breast Cancer Genetic Screening

Early detection of breast cancer increases a woman’s treatment options and chances for survival. Breast cancer genetic testing can alert a woman to an increased risk of the disease, allowing her to make lifestyle changes and take preventative measures.

Inherited Risk for Breast Cancer

The American Cancer Society (2009) reports that approximately 5 to 10 percent of breast cancer cases are caused by inherited genetic abnormalities to a breast cancer gene.

Inherited changes to the genes BRCA1 and BRCA2 are known to greatly increase the risk of breast cancer and ovarian cancer. Breast cancer genetic testing can detect both of these mutations.

Several risk factors suggest the presence of alterations to BRCA1 and BRCA2. You might consider breast cancer genetic testing for these two genetic markers if you have any of the following:

  • Ashkenazi (Eastern European) Jewish ancestry
  • Breast cancer in a family member before the age of 50
  • Family history of ovarian cancer
  • Family history with more than one generation of breast cancer
  • Family member with bilateral breast cancer (cancer in both breasts)
  • History of breast cancer in two or more immediate family members
  • Male relative who has breast cancer
  • Personal history of breast cancer at a young age
  • Relative whose breast cancer genetic screening confirmed either BRCA1 or BRCA2
  • Relative with both ovarian and breast cancer.

Breast Cancer Genetic Testing

To get a genetic test performed, you must provide a blood sample to be delivered to the breast cancer genetic testing lab for analysis. At the lab, your DNA is examined for signs of alterations in BRCA1, BRCA2 and other genetic markers known to raise the risk of breast cancer.

Breast cancer genetic testing continues to reveal new gene markers as medical research uncovers more inheritable cancer risks. It can take several weeks for a breast cancer genetic testing lab to return test results.

Interpreting Breast Cancer Genetic Testing Results

Approximately 10 percent of breast cancer genetic testing results indicate BRCA1 or BRCA2 mutations, but not the changes known to increase the risk of breast cancer; many of these genetic alterations are thought to be harmless.

Estimates vary, but the presence of BRCA1 or BRCA2 genetic alterations increases the lifelong risk of breast cancer from 13 percent to between 60 and 80 percent, as reported by the American Cancer Society (2009).

If test results indicate that you don’t have the BRCA1 or BRCA2 alterations, this doesn’t mean that you won’t develop breast cancer. You still have the same risk as the general female population: one in eight, according to the National Cancer Institute (2009).

On the other hand, if it does indicate the presence of BRCA1 or BRCA2 alterations, this doesn’t necessarily mean that you’ll develop breast cancer. It only means that you’re in a higher risk group for the condition.

Resources

American Cancer Society. (2009). Breast cancer facts and figures 2009-2010. Retrieved on October 11, 2010 from http://www.cancer.org/acs/groups/content/@nho/documents/document/f861009final90809pdf.pdf

Mayo Clinic. (2008). BRCA gene test for breast cancer. Retrieved October 12, 2010 from http://www.mayoclinic.com/health/brca-gene-test/MY00322

National Cancer Institute. (2009). BRCA1 and BRCA2: Cancer risk and genetic testing. Retrieved October 20, 2010, from http://www.cancer.gov/cancertopics/factsheet/risk/brca