BRCA1 & BRCA2

BRCA1 and BRCA2 are two genes that are linked to breast cancer. A mutation in either gene increases a woman's lifetime risk for breast and ovarian cancers. Women who inherit these gene mutations usually have an increased risk of developing breast cancer at a younger age (before menopause), and often have multiple close family members with the disease.

About 50% to 85% of women with a BRCA1 or BRCA2 mutation will get breast cancer, compared to 12% in the general population. About 5% to 40% of women with a BRCA1 mutation and 10% to 20% of women with a BRCA2 mutation will get ovarian cancer, compared to 1.5% in the general population.

These wide estimates reflect the fact that actual risks are different from one woman to another. Although these estimates can be useful for considering risk in large groups of people, they cannot predict an exact risk in any one individual. Screening recommendations for women with BRCA1 or BRCA2 mutations:

Monthly breast self-exam
Clinical breast exam, annually or bi-annually starting at age 25-35
Mammography, annually or bi-annually starting at age 25-35
Transvaginal unltrasound, annually or bi-annually starting at age 25-35 (ovarian cancer)
Rectal exam, prostate-specific antigen test, annually starting at age 50 (prostate cancer)
Fecal occult blood test annually and flexible sigmoidoscopy every 3-5 yrs starting at age 50 (colon cancer)

National Cancer Institute, "Genetic Testing for Breast Cancer Risk: It's Your Choice," 1997.

Burke et al (1997). "Recommendations for follow-up care of individuals with an inherited predisposition to cancer," JAMA, 227: 997-1003.