Understanding the BRCA 1 and 2 Gene Mutation – Hereditary Breast and Ovarian Cancer (HOBC)
Almost every one of us has known a close family member or friend that has been affected by breast or ovarian cancer. We have seen the devastation that it has taken on patients and their loved ones. In the past many families would have generations of women affected with either breast or ovarian cancer. With many years of research, the medical field has been able to find a major piece of the hidden puzzle.
BRCA 1 and 2 Gene Mutation
All cancer results from an accumulation of mutations in genes that normally control cell division. Most of these mutations are acquired during a person’s lifetime. In some individuals, an initial mutation in a critical gene is inherited. Approximately 7% of breast cancer and approximately 14% of invasive ovarian cancer results from such genetic mutations passed down from either the father or the mother. The majority (approximately 84%) of hereditary breast and ovarian cancer results from inherited mutations in two genes called BRCA1 (52%) and BRCA2 (32%). Although sometimes referred to as the “breast cancer genes,” BRCA1 and BRCA2 are also associated with the majority of hereditary cancers of the ovary.
Who is at Risk for Breast and Ovarian Cancer?
As a gynecologist and obstetrician, I ask my patients detailed questions focusing on both the mother’s and the ‘s father side of the family. Many times people have a misconception that these gene mutations can only come from the mother’s side of the family. This is far from being true. An individual has an equal risk from obtaining the gene mutation from the mother or the father. As a health care provider, I look for red flags that tell us someone is at risk. Individuals with a personal history of, or a close blood relative (1st, 2nd, or 3rd degree in the maternal or paternal lineage) with, any one of the red flags is at increased risk of HBOC.
Risk factors and red flags include a family history of:
- Ovarian cancer
- Breast cancer < age of 50
- Two primary breast cancer in one family
- Triple negative breast cancer
- Pancreatic cancer with another HBOC cancer
- Ashkenazi Jewish ancestry with another HBOC cancer
- Family history of a previous identified family member
Why We Test for BRCA
It has been estimated that in a general OBGYN practice, at least one in every ten women are at risk. One of my most memorable experiences that I had was when I met with was a patient who had a paternal aunt with breast cancer at 55 and a paternal cousin with breast cancer at 40. The most effective way to evaluate the patient would be to test the affected family members for the gene mutation. If the family members are unable to be tested, then the unaffected patient should undergo testing. For the above mention patient, she underwent testing and was found to be positive for the BRACA2 mutation.
With this gene mutation, a patient has a 50% chance of developing breast cancer by age 50 and up to 87% chance of developing breast cancer the age of 70 (compare to 8% of general population). With regards to ovarian cancer, A BRAC affected patent has a 44 % of developing ovarian cancer.
Many people are hesitant to be tested because they believe the misconception that there is nothing that can be done about cancer. This is far from the truth. Medical and surgical management is used very effectively in identifying and reducing cancer. The National Comprehensive Cancer Network (NCCN) recommends the initiation of clinical breast examinations, mammography, and MRI at age 25 for BRCA1/2 mutation carriers. For ovarian cancer screening, NCCN recommends pelvic examination, pelvic ultrasound and CA 125 blood test every 6 months. Early detection helps to reduce cancer deaths. It has been shown that oral contraceptives reduce the risk of ovarian carcinoma in both BRCA carriers and non-carriers. Studies have shown, women with mutations in BRCA1 or BRCA2 that demonstrated that the use of oral-contraceptives for 6 or more years was associated with a 60% reduction in the hereditary risk of ovarian cancer. Selective estrogen receptor modulators (SERMs), like tamoxifen, can decrease the risk of breast cancer in high risk patients. One study reported that tamoxifen reduced breast cancer incidence by 62% among healthy women with BRCA2 mutations.
For surgical management, Prophylactic oophorectomy reduces the risk of ovarian cancer by up to 96% in women with BRCA mutation. Prophylactic oophorectomy has also been shown to reduce the risk of breast cancer by up to 68% in women with BRCA1 and BRCA2 mutation. Prophylactic mastectomy has been shown to reduce the risk of breast cancer in high risk women by more than 90% and studies have demonstrated that prophylactic mastectomy specifically reduces the risk of breast cancer in women with mutations in BRCA1 or BRCA2 by 89.5% to 100%. Such decisions must be highly discussed between the patient and physician in an individualized manor.
Knowledge is Power!
Women with significant family history can make informed decisions to reduce the risk of developing cancer. Not only are they at risk, but the family members that they are raising are at risk. In the above mentioned patient that was diagnosed with BRACA mutation she decided to undergo surgical intervention by removal of both fallopian tubes and ovaries because she decided she wouldn’t be bearing any additional babies. The final pathology report showed early cancer that was contained! If this had continued to grow without the surgery the prognosis would have been bleak.
Without this test, she would have been another statistical death. Now she can live a full life and enjoy interacting with her grandchildren as they grow up! Priceless!!!
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