PETER CHIN
FAMILY HISTORY/ GENETIC TESTING
Some women have a strong family history of breast and/or ovarian cancer. This is usually manifested as close family members developing breast cancer at a younger age (<50 years old), bilateral breast cancer or ovarian cancer. Family members who are carriers of the BRCA gene mutation (BRCA 1 and BRCA2) have a 60-80% risk of developing breast cancer and 20-40% change of developing ovarian cancer in their lifetime.
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It is recommended that women with a strong family history should have a discussion with a breast specialist for advice regarding screening and preventative measures. They may be referred to a genetic service for consideration of genetic testing. In the Bay of Plenty, referrals are made to the Northern Regional Genetic Services based in Auckland for consideration of genetic counselling and testing.
A family history risk assessment is made and those with a very high likelihood of carrying a genetic mutation is then offered testing. For the initial genetic testing, only the index affected case (i.e. the person who has had breast or ovarian cancer) is tested.
If a mutation is found, the genetic test is then offered to other family members. If a mutation is not detected, it could mean that either the individual does not carry a mutation, or that a mutation is present but could not be detected with current testing technology. That individual should continue to be vigilant with breast awareness and have regular breast screening performed every year.
Women with a high risk family history should have annual mammography, starting approximately 5 – 10 years earlier in relation to the age at which the youngest affected case was diagnosed. Consideration should also be made for the use of annual screening Breast MRI for women with a very strong family history and those confirmed to carry the BRCA mutation. Breast MRI is highly sensitive in detecting abnormal lesions but as a result of it’s sensitivity, various other benign unrelated lesions may be detected at the same time. This may require further evaluation with a “2nd Look” Ultrasound and core biopsies may be necessary. It is advisable for the individual to have a discussion with a breast specialist regarding these issues to decide whether MRI is indicated.
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In addition, women with a confirmed BRCA mutation should have a discussion with regards to preventative measures. This may include the use of therapeutic agents e.g. Tamoxifen , to reduce the risk of developing cancer. This is commonly referred as “chemoprevention”, a term that can be misleading, as it does not involve the use of chemotherapy drugs. Prophylactic Mastectomy and Immediate reconstruction should be discussed, as well as the role of prophylactic salpingo-oophorectomy (removal of ovaries and tubes to prevent ovarian cancer).
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In summary, the topics that need to be addressed for individual with a strong family history are as follows:
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Whether a referral should be made to the genetic services
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Breast awareness and self examination
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Breast screening/ surveillance
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Any need for ovarian screening
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Preventative measures e.g. therapeutic agents, lifestyle etc.
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Preventative surgery