For about five to 10 per cent of women diagnosed with breast cancer, hereditary factors are the root cause.
In fact, having a first-degree (mother, sister, daughter) relative with breast cancer, increases the potential that you are carrying a mutated breast cancer gene.
And women who inherit a gene mutation have a much higher risk of developing breast cancer.
A gene can often harbour an abnormality that changes how the cell works or responds to its environment. According to Sara Carroll, genetic counsellor at Cleveland Clinic Florida, “the most common causes of hereditary breast cancer include mutations in the BRCA 1 and BRCA 2 gene”. There are other hereditary causes of breast cancer, but these are the most prevalent. These genes can be inherited from either parent.
BRCA genes help to correct DNA damage. In people with a mutation in BRCA1 or BRCA2, the ability to repair damage is impaired and can sometimes lead to breast cancer. This suggests an estimated 87 per cent lifetime risk of developing breast cancer, which begins to rise steeply at the age of 30. The risk of developing breast cancer by the age of 50 is approximately 50 per cent.
There are several factors that can suggest the possibility that hereditary breast cancer runs in your family. You should be concerned if:
• There is both breast and ovarian cancer in your family.
• Diagnosis of breast cancer has occurred before age 50.
• Diagnosis of bilateral breast cancer (cancer in both breasts).
Ask about genetic counselling if you are concerned, or call for a risk assessment appointment if you are unsure. High-risk women can be tested to screen for mutations in the BRCA genes.
“Genetic testing can be beneficial in determining whether a cancer diagnosis was random or the result of an inherited mutation,” says Ms Carroll.
This is valuable information, as there may also be an increased risk for other cancers as well. Your family members will also benefit from discovering whether a hereditary risk exists.
At the genetic counselling visit, a personal and detailed family medical history will be obtained. Depending what your hereditary risk factors are, we can determine whether or not genetic testing is appropriate, and which genetic changes to assess. Genetic testing involves a blood test, and the results are typically known in a few weeks.
Hereditary risk assessment and genetic testing have become tools in the personalisation of breast cancer treatment, by providing a basic understanding of the structure and function of genes at a molecular level. This knowledge allows the best clinical management to be determined. In some instances, additional breast cancer risk management options may be necessary. Tell your doctor about your family history of breast cancer and discuss whether that history might support the consideration of changes to your care.
The Breast Center at Cleveland Clinic Florida is fully accredited by the National Accreditation Program for Breast Centers (NAPBC), a designation given to centers that are committed to providing the highest quality breast care. The breast cancer team provides the most up-to-date information on the genetic components of breast cancer, and offers predictive testing for family members who may have inherited a specific genetic mutation.
“Understanding the increased genetic risk enables you to evaluate your options in advance. Working with our breast cancer care team, you can create a personalised plan, designed to prevent or detect cancer at an earlier and more treatable stage,” Ms Carroll says.
Women can be empowered to make important health decisions, armed with the knowledge of their genetic breast cancer risk.