Have you ever wondered what the underlying building blocks of your DNA tell you about your unique health road map? Knowing information about our DNA tells part of our story of what might affect our health. For some people, knowing about their DNA might provide invaluable insights that could encourage a change in behaviors or influence decisions about prevention or treatment.
The news is filled with information about DNA mapping. Anyone can provide a saliva or blood sample and companies such as Invitae, Myriad, Pathway Genomics, GeneDx or 23 and Me can return a genetic profile about risk for specific diseases. For instance, Angelina Jolie made a monumental decision to have a preventive mastectomy on the basis of information that she had about her DNA. As a carrier of the BRCA1 mutation, she decided to have a bilateral mastectomy. Because she has the BRCA1 mutation, that drastic surgery reduced her risk of breast cancer by up to 95 percent. Bilateral mastectomy can reduce the risk of dying of breast cancer up to 90 percent in women who have a strong family history of breast cancer as well, according to the National Cancer Institute.
I was an oncology nurse and spent a lot of time thinking about risk, especially related to lifestyle and environmental factors. I lived a healthy lifestyle and never imagined that I was a woman “at risk.”
In the case of breast cancer, the challenge is to determine who falls into the category of having a family history. For me, my father’s mother had breast cancer when she was in her 40s and my mother’s sister had breast cancer in her late 50s, but there were no other cases of breast cancer. I shared this history with my internists and OB/GYNs over the years but it never raised a red flag. I was an oncology nurse and spent a lot of time thinking about risk, especially related to lifestyle and environmental factors. I lived a healthy lifestyle and never imagined that I was a woman “at risk.”
When I was diagnosed with breast cancer at the age of 40 while nursing my fourth child, I was shocked. I assumed I had all the protective factors that would prevent me from getting breast cancer, but yet here I was. After my diagnosis, I was tested to see if I was a carrier of the BRCA gene mutation. In 2006, that was the mutation most associated with breast cancer. The test showed I did not carry the BRCA mutation, but I sensed then that I must have some genetic mutation. It may have been my way of trying to explain this horrible turn of events, but I wanted a reason.
If I had known of my “risky” history, then I would have started surveillance at an earlier age and might have had a different outcome.
I remember being told at the time of my diagnosis that my breast cancer had probably been growing in me for at least five years. But unfortunately, I was not due to have my first mammogram until I was 40. If I had known of my “risky” history, then I would have started surveillance at an earlier age and might have had a different outcome.
Knowledge is Power
Knowledge is power. Although genetic testing aimed at helping to prevent breast cancer is still far from a perfect process, it has its place. About 5 percent to 10 percent of breast cancers are thought to be hereditary, caused by abnormal genes passed from parent to child. The average woman in the United States has about a 1 in 8, or about 12 percent, risk of developing breast cancer in her lifetime. With a genetic mutation, that risk can be anywhere from 40 percent to 80 percent. More women are now being offered gene-testing panels that look not just for mutations to BRCA1 and 2, but also to ATM, CHEK2, and PALB2 — all of which are genes in which mutations may increase the risk of breast cancer. If a woman has one of those genes, screening for breast cancer starts at the age of 30, instead of 35 or 40.
The average woman in the United States has about a 1 in 8, or about 12 percent, risk of developing breast cancer in her lifetime. With a genetic mutation, that risk can be anywhere from 40 percent to 80 percent.
As a result of my belief that I could likely be a mutation carrier, I had genetic testing, which showed I carry a mutation in the CHEK2 gene. This likely explains my early breast cancer diagnosis. Nevertheless, some skeptics say that widespread genetic testing will only result in more testing. In other words, more people getting genetic testing may result in more testing for disease and more discovery of “disease” even though the condition in question may never fully express itself. But, genetic testing can also spare people from too much treatment. For instance, my sister used the information from her genetic testing to choose a less aggressive form of treatment for a precancerous lesion, knowing she was at less risk based on her genetic profile. I say, we won’t know the value of genetic testing until we have more data.
… my sister used the information from her genetic testing to choose a less aggressive form of treatment for a precancerous lesion, knowing she was at less risk based on her genetic profile.
I feel strongly that there is a real opportunity to improve health based on information gleaned from genetic testing that was not previously available. Knowing my DNA results has been a gift to my family. Family members who also test positive for the mutation will be able to have closer monitoring as a result of this knowledge. I will also be more closely followed for other potential cancers associated with the CHEK2 mutation.
If you can answer yes to any one of the questions below, it would be appropriate to consider genetic testing.
|Did any of your first-degree (parents, brothers, sisters, children) relatives have breast or ovarian cancer?|
|Did any of your relatives have breast cancer in both breasts?|
|Did any man in your family have breast cancer?|
|Did any woman in your family have breast and ovarian cancer?|
|Did any woman in your family have breast cancer before age 50?|
|Do you have 2 or more relatives with breast and/or ovarian cancer?|
|Do you have 2 or more relatives with breast and/or colon cancer?|
First-degree = parents, brothers, sisters, children
Second-degree = aunts, uncles, nieces, nephews, grandparents, grandchildren
Ashton-Prolla P, Giacomazzi J, Schmidt AV, Roth FL, Palmero EI, Kalakun L, et al. Development and validation of a simple questionnaire for the identification of hereditary breast cancer in primary care. BMC Cancer. 2009;9:283.