Written by SMH Certified Genetic Counselor Nicole Wood
Most cancer is sporadic, caused by a combination of environmental factors and lifestyle habits that accumulate and that take their toll over time. In fact, aging is the primary risk factor for developing cancer.
Thankfully, each of us is born with a number of genes designed to protect us from cancer by countering these external factors. As we age, however, these risk factors and lifestyle habits chip away at our genetic protection, gradually increasing our risk of developing cancer.
When breast and other cancers are prevalent within a family, it could be because the relatives have similar lifestyle habits or live in the same area and have the same environmental exposures. Occasionally, though, the increased cancer risk is inherited: a mutation in the genetic code that is passed down from generation to generation.
Testing for Hereditary Cancer
Genetic testing for hereditary breast and ovarian cancer began in the late 1990s, when scientists discovered that changes within the protective BRCA1 and BRCA2 genes often increased a woman’s likelihood of developing female breast cancer or ovarian cancer. The scientists identified these crucial genes by studying families with generations of women diagnosed with these cancers and found that in each family, the BRCA1 or BRCA2 genes had mutations.
Just like all fields of medicine and technology, genetic testing has improved over time. Until 2013, BRCA1 and BRCA2 were essentially the only two genes looked for when investigating why cancer may be running in a family. But in the last several years, genetic testing has significantly expanded thanks to evolving technology and a better understanding of the human genome. Researchers continue to learn more about how genes impact cancer risk, and now, up to 47 genes can be tested for at the same time.
Modern Genetic Testing
These leaps in genetic testing mean that people who have a family history of cancer and previously tested negative for BRCA1 and BRCA2 mutations should consider further testing with today’s improved capabilities.
There is a chance that these newer, updated tests may identify a hereditary cancer syndrome or that a re-evaluation of the BRCA1 and BRCA2 genes offers more information than before. This invaluable information can be used to develop a customized plan for cancer surveillance, screening and prevention.
With the addition of so many other genes to evaluate, genetic tests are identifying more hereditary causes for cancer than ever before. We now know there are genes that can link breast cancer and colon cancer; breast cancer and pancreatic cancer; colon cancer and uterine cancer; and more.
In regard to your own family history of cancer, it’s important to consider all types of cancers — most families with hereditary cancers have more than one type of cancer in the family — and both sides of your family; you can inherit a breast cancer gene from your father just as you can from your mother.
Knowledge Is Power
Finding out that you may be at a higher risk for developing cancer than the average person can be daunting and overwhelming. So why would you want to know? Because that knowledge can give you and your healthcare team the power to do something about it, to create a specific plan for screening or other potentially life-saving interventions.
Early detection is key to diagnosing cancer at its most treatable stage.
For example, if genetic testing finds that you’re at increased risk for breast cancer, your doctors likely will advise you to start getting mammograms or other breast imaging tests at age 25 — which is much earlier than the recommended age for the average-risk woman (age 40) — and more frequently, perhaps every six months instead of annually. Your healthcare team could also recommend a risk-reducing surgical intervention such as a mastectomy.
If you’re at an increased risk for colon cancer, your doctors won’t want you to wait to get screened until age 50 (the recommended age for average-risk people), but likely will recommend screening at a younger age and at more frequent intervals.
Conversely, if a hereditary cancer syndrome is identified in your family, anyone who tests negative for it is considered to be at an average risk for developing cancer — despite the family history — and they would not need the increased screening. Additionally, this would mean that they cannot pass the gene down to future generations, a huge relief for concerned loved ones.
Nothing about who you are changes when you do genetic testing. It just allows your cancer surveillance to be personalized to your risk, rather than the one-size-fits-all approach designed for those who are at average risk.
Genetic testing offers knowledge and insight into a predisposition for cancer — or lack of — that’s invaluable, not only to the person being tested and his/her healthcare team but also to everyone in his/her family.
If you are worried about your family’s cancer risk or are interested in learning more about genetic testing and how it can support your wellness, check out our Frequently Asked Questions and fill out our family history quiz. You can also reach the Sarasota Memorial Genetic Counseling and Education office at 941-917-2005.
Nicole Wood, MS, CGC, is the only licensed and board-certified genetic counselor serving Sarasota County and its surrounding communities. Specialty trained in oncology genetic counseling, Wood works closely with the multidisciplinary Genetic Counseling and Education team at Sarasota Memorial to provide expertise for patients’ clinical care.