Bianca Rossouw, a genetic counsellor, explains how faulty genes can cause cancer and why consulting with a genetic counsellor is beneficial if you have a family history of related cancers.
What is a genetic counsellor?
Genetic counsellors are healthcare professionals who assess individual or family risk for a variety of inherited conditions, including hereditary cancer syndromes. We provide individuals with information to help them understand how a genetic condition can affect them and their family; how the condition is inherited; and identify which individuals in a family are at risk of the condition.
We can recommend when and what type of genetic testing is appropriate, interpret genetic test results and explain them in a meaningful way, and discuss management and treatment options.
We are also trained to provide appropriate psychosocial counselling and support to individuals and assist with decision-making. Finding out that there is a genetic condition in the family can be extremely overwhelming, and so it’s important to explore individuals’ emotions and experiences.
Most cancers occur by chance; we call these sporadic cancers. However, in approximately 10% of cases (depending on the type of cancer) the cancer is caused by a faulty gene that is being passed down in the family. We call these hereditary cancers.
We are more concerned that there might be a hereditary cancer syndrome in a family when there is a young age of onset (<40 years for breast cancer); individuals affected with multiple cancers or bilateral disease; multiple generations affected; a family history of related cancers (breast and ovarian cancer); the presence of rare types of cancer (male breast cancer); or if the family is from a high-risk population group (Ashkenazi Jewish or Afrikaner ancestry). Individuals with any of these risk factors should be referred to a genetic counsellor.
Hereditary breast and ovarian cancer syndrome
There are multiple genes that have been associated with a number of hereditary cancer syndromes. These genes are associated with different cancer risks. One of the most common hereditary cancer syndromes is hereditary breast and ovarian cancer syndrome (HBOC), caused by mutations in the BRCA1 and BRCA2 genes. HBOC is associated with a high risk of developing breast, ovarian, prostate and pancreatic cancer.
Cost and process
Once a patient is referred to us, we perform a risk assessment to see if genetic testing is indicated. Depending on the types of cancers that an individual or the family presents with, the genetic counsellor will advise what genes we should consider testing, as there are over 20 genes that have been associated with hereditary breast and ovarian cancer alone. Most medical aids will cover the cost of a genetic counselling consultation, and some genetic testing options are covered too. This is usually claimed from the medical savings account. While genetic testing is more expensive than routine blood tests, it can be done for approximately R5 000.
Treatment and management
Earlier referral to a genetic counsellor can be advantageous because treatment and management can be tailored if a hereditary cancer syndrome is diagnosed. Increased screening or prophylactic surgery (bilateral mastectomy or bilateral salpingo-oophorectomy) can be considered to reduce one’s risk of developing cancer.
In addition, there may be targeted treatment options available for individuals who have certain genetic mutations, such as treatment with PARP inhibitors.
There are also important implications for biological relatives. Once a mutation has been identified, genetic counselling and testing can be offered to at-risk family members. Individuals who are diagnosed with a hereditary cancer syndrome before they have had children may also be interested in finding out about ways to prevent passing on the faulty gene. Good news, your genetic counsellor can help you with this too.
One of the most common things I’ve heard patients say is “My cancer can’t be hereditary, there is no one else in my family with cancer.” Well actually, it can still be hereditary. Genetics can be complicated and confusing, but once you have consulted with your genetic counsellor, you’ll feel at ease and be equipped with all the information and support that you need to make empowered decisions about your health.
MEET THE EXPERT – Bianca Rossouw
Bianca Rossouw is a genetic counsellor and lecturer at the National Health Laboratory Service and the University of the Witwatersrand. She practices in the state healthcare sector and is also a member of a private practice based at the Wits University Donald Gordon Medical Centre. She sees a variety of patients including prenatal, paediatric and adult cases. She has a special interest in hereditary cancer syndromes and is currently pursuing a PhD in this field.
Header image by Adocbe Stock