Understanding the BRCA gene and its role in breast cancer risk
As South Africa joins the global community in observing Breast Cancer Awareness Month during October, which is commonly referred to as "Pink Month", the focus sharpens on raising awareness, educating the public and promoting early detection of breast cancer.
This month serves as a crucial reminder that breast cancer affects not only women but also men, and it can have a profound impact on families across generations.
To shed more light on the role genetics play in breast cancer, Independent Media Lifestyle sat down with one of South Africa’s leading oncologists, Dr Lisa Dalmeyer, who shared valuable insights into the BRCA gene and its significance in breast cancer risk.
Dalmeyer, a passionate community service leader, and a graduate of the University of Cape Town, has extensive experience in various medical disciplines, including internal medicine, surgery and paediatrics.
In recent years, her focus has shifted to oncology, where she has become a trusted voice in understanding genetic risks for cancer, notably the BRCA gene mutation.
What is the BRCA Gene?
One of the key elements in understanding breast cancer risk is the BRCA gene. According to Dalmeyer: “We all have BRCA genes in our cells.”
These genes are responsible for repairing DNA and ensuring that cells don’t become abnormal. However, when there is a mutation or defect in these genes, the body’s ability to repair damaged cells is impaired, leading to an increased risk of cancer.
“The problem arises when these genes become defective,” Dalmeyer explained. That’s when the risk of cancer, particularly breast and ovarian cancer, begins to increase.
BRCA1 v BRCA2
When discussing the BRCA gene, it’s important to note that there are two types: BRCA1 and BRCA2. Both mutations increase the risk of breast and ovarian cancer, but BRCA1 carries a higher risk.
“BRCA1 is more aggressive,” Dalmeyer said. The lifetime risk of developing breast cancer with a BRCA1 mutation is between 55% and 65%, while the risk of ovarian cancer can be as high as 40%.”
In comparison, BRCA2 carries a slightly lower risk, with about a 40% to 45% chance of developing breast cancer and a 10% to 17% chance of ovarian cancer.
Who should be concerned about BRCA mutations?
Individuals with a noteworthy family history of breast or ovarian cancer are often referred to genetic counsellors, who will construct a family tree or “anagram” to assess their risk for BRCA mutations.
Testing can be conducted via blood or saliva samples, followed by post-test counselling to discuss results and their implications for both the individual and their family.
Dalmeyer highlighted that “Certain ethnic groups, such as Ashkenazi Jews, have a higher prevalence of BRCA mutations,” indicating that awareness can be particularly beneficial in these communities.
“Male breast cancer, although rare, is a red flag, she noted. “Men with breast cancer or those with a family history of prostate or pancreatic cancer should definitely consider genetic screening.”
The impact of a BRCA-positive diagnosis
Testing positive for a BRCA mutation can be life-changing, but Dalmeyer emphasised that it’s not a definitive cancer diagnosis.
“In the past, knowing you had a BRCA mutation was more of a ‘nice-to-know’ situation,” she explained.
“But today, We can intervene earlier now,” Dalmeyer said, pointing out that some women with BRCA mutations opt for preventive mastectomies or oophorectomies (removal of the ovaries) to dramatically reduce their risk of developing cancer.
If you’ve tested positive for a BRCA gene mutation, your focus should be on prevention and early detection. She reassured that guidelines are similar for both BRCA1 and BRCA2 carriers.
Starting at age 25, it's important to have regular breast exams. By age 30, you should begin annual imaging, either a mammogram or an MRI.
For younger women, especially those with dense breast tissue, an MRI is often recommended because it's more effective at detecting issues.
In addition to breast monitoring, keeping up with gynaecological exams is crucial for ovarian cancer prevention. This includes semi-annual transvaginal ultrasounds to check your ovaries, along with a blood test called CA-125, which helps detect ovarian cancer markers.
However, it's important to note that getting MRIs can be challenging. They are expensive, and many insurance companies may not cover screening costs.
Advocating for your health and understanding your options is key to managing your well-being when dealing with a BRCA mutation.
“The preventive strategies available today are far more advanced than they were just a decade ago.”
Breast cancer remains one of the most common cancers affecting women in South Africa. According to the National Cancer Registry, about one in every 27 women in the country will be diagnosed with breast cancer in their lifetime.
The Cancer Association of South Africa (Cansa) also reports that early detection can significantly improve survival rates, with a 90% five-year survival rate for those diagnosed in the early stages of the disease.
However, the challenge remains in ensuring that all South Africans, particularly those in underserved areas, have access to early detection and treatment.
The cost of genetic testing for BRCA mutations can be prohibitive for many, though various organisations are working to make these tests more accessible.