About 5% to 10% of all breast cancers happen in women with inherited abnormal BRCA1 and BRCA2 genes.
The average woman (without an inherited breast cancer gene abnormality) in the United States has about a 12% risk of developing breast cancer over a 90-year life span.
In contrast, women who have an abnormal BRCA1 or BRCA2 gene have up to an 85% risk of developing breast cancer by age 70. Women with BRCA1 and BRCA2 abnormalities also are at increased risk of developing ovarian cancer. The lifetime risk is about 55% for women with BRCA1 mutations and about 25% for women with BRCA2 mutations.
Women who have an abnormal BRCA1 or BRCA2 gene and want to be as aggressive as possible in reducing their risk of breast (and ovarian) cancer may consider surgery to remove their ovaries and fallopian tubes. This surgery is called salpingo-oophorectomy.
A study followed 89 women with either an abnormal BRCA1 or BRCA2 gene who chose to have their ovaries removed. Like earlier research, this study showed that removing the ovaries reduced the women's risk of breast cancer. However, earlier research showed that salpingo-oophorectomy had the greatest benefit in women younger than 40. This study showed that salpingo-oophorectomy had benefits for women who were about 51 at the time of surgery.
Of the 89 women in the study, 73 women ALREADY HAD BEEN TREATED for breast cancer before their ovaries were removed. During the 10-year follow-up period after surgery, about 70% had no new breast cancers. The other 30% had the cancer come back in the same or the opposite breast (14 women) or had the cancer spread beyond the breast (8 women).
Sixteen of the 89 women in the study DID NOT HAVE BREAST CANCER BEFORE they decided to have their ovaries removed. Three of them, or about 19%, developed breast cancer during the 10-year follow-up period. But the other 13 (about 81%) did not.
Four of the 89 women died during the 10-year follow-up period, three from breast cancer and one from pancreatic cancer. Four of the women had early signs of cancer in their ovaries or fallopian tubes when they were removed.
If you know you have an abnormal BRCA1 or BRCA2 gene, you need practical guidelines and information.
- Develop an aggressive breast cancer screening plan. You and your doctor should develop a special plan of breast cancer screening, including more frequent screenings starting at an early age and possibly using other techniques (such as MRI scans) beyond routine mammograms. And monitoring for ovarian cancer is a must as well.
- Modify your lifestyle. There are many diet, exercise, and lifestyle changes that every woman, including those with genetic abnormalities, can take to lower her risk.
- Consider all the options for reducing your risk and create a plan that's right for YOU. Hormonal treatments, mastectomy, and removing the ovaries are all possible options to lower your risk. Together, you and your doctor can plan the approach that’s right for you. Certain family planning choices also may help lower your risk, including having children at a relatively early age (but only if you're ready to become a parent, of course).
To learn more, visit the Breastcancer.org Breast Cancer Risk Factors: Genetics page.