In collaboration with Lorna Jane at Huntington Beach, ScientiFIT brings you an informative lecture on
Published on May 23rd, 2013 | by Michelle Wedemeyer, M.D., Ph.D.0
Hereditary Breast Cancer: Should I Be Screened?
Recent headlines have been filled with a discussion about testing for and the drastic treatment of women with inherited errors in the genes BRCA1 and BRCA2. A critical component of this discussion is the cost of testing, which is on the order of thousands of dollars, and the drastic nature of the treatment, which may involve surgical removal of both breasts and ovaries. While the impact of these mutations on the chances of developing breast and ovarian cancer is undeniable, the mutations are actually quite rare at approximately 1/300-500 compared to the 1/8 women who will develop breast cancer. Thus the majority of women, and even the majority of women who either get breast cancer themselves or have a family history of cancer, do not carry this mutation.
This being said, BRCA1 and BRCA2 contribute to approximately 5-10% of breast cancers diagnosed in the United States. Similarly, between 39-46% of BRCA1 and 12-20% of BRCA2 carriers will develop ovarian cancer, which is generally detected at an advanced stage and is one of the most lethal cancers in women. This makes the identification of mutation carriers a priority so their family members can be identified before the development of cancer and screened appropriately with frequent breast imaging and ultrasounds of the ovaries. Similarly, the treatment of women with inherited breast cancers is far more aggressive than that of women who do not carry mutations.
Fortunately, there are several characteristics of hereditary breast cancers, which assist with the identification of women who carry the genes:
- Hereditary cancers tend to occur at a young age (<40 years)
- Hereditary cancers tend to occur in both breasts
- Hereditary cancers tend to be more aggressive
- Hereditary breast cancers tend to affect multiple blood relatives on the same side of the family
Thus, the U.S. Preventative Services Task Force and the American College of Obstetricians and Gynecologists have developed a set of guidelines as to which women have a high probability of carrying these mutations. In general, these include:
- Women who develop breast cancer at a young age, particularly before menopause
- Women who develop breast cancer in both breasts
- Women who develop ovarian cancer, fallopian cancer, or peritoneal cancer
- Women who develop breast cancer at a young age (<50) and have one close relatives (sister, mother, aunt, grandmother) with breast cancer at a young age
- Women who develop breast cancer at any age with at least two close relatives with breast cancer
- Women who do not have symptoms but have a close blood relative with a known BRCA mutation
The vast majority of women do not meet these criteria and thus, are at very low risk of carrying a mutation in BRCA1 or BRCA2. In families where any of these higher risk features are present, testing should start with a family member who has been diagnosed with cancer rather than a healthy family member.
1) Genetic Risk Assessment and BRCA Mutation Testing for Breast and Ovarian Cancer Susceptibility: Recommendation Statement. U.S. Preventative Services Task Force
2) Practice Bulletin #103 “Hereditary Breast and Ovarian Cancer Syndrome” The American College of Obstetricians and Gynecologists