Genetic Testing for Cancer: Does the Disease Run in Your Family?

By Christina Bhattacharya January 30, 2016 Posted in: Cancer Care , Article

Cancer is an illness that will affect many of us at some point in our lives, either directly or through close relatives or friends. What's more, people who have a family history of cancer may be more likely to develop it themselves. Over the past four decades, however, researchers have made extraordinary advances in the discovery and treatment of most major cancers. The result? A remarkable rise in cure rates and long-term survival for people diagnosed with recognized and extensive cancers, such as breast and prostate cancers. Genetic testing for cancer is an example of technology that helps in terms of identification by finding out if a specific cancer runs in your family.

Cancer and Genetics

There are many known hereditary cancer syndromes that are attributed to genetic mutations. The most common of these include breast cancer, colorectal cancer, ovarian cancer, prostate cancer, and endocrine cancer. Genetic testing specifically looks for inherited changes or mutations in your chromosomes, genes, or proteins.

Because about 5–10 percent of all cancers are inherited, harmful genetic mutations can be passed from one blood relative to another. Those who inherit abnormal genes have a higher chance of developing cancer at an earlier age. Genetic testing can help you conclude whether other family members have inherited the same genetic mutation.

Your Family Cancer History

If you decide to undergo genetic testing, your doctor will first request information on the cancer history of your first- and second-degree relatives. This will include the cancer types of all family members, the age each person was diagnosed, whether the person was a maternal or paternal relative, the relative's ethnicity, and results of any previous genetic testing for cancer. Based on this information, your doctor will create a screening and prevention plan that focuses on specific inherited cancers, as well as risks for other cancers. Your doctor may suggest genetic testing to determine if you inherited mutated genes.

Public Interest Is Rising

The general awareness of genetic testing for cancer increased in 2013 following superstar actress and director Angelina Jolie's public confession about her decision to have a preventive double mastectomy. The decision came following genetic testing that exposed many factors, including that she carried the mutated gene, BRCA1, which greatly increased her risk of developing breast and ovarian cancers. Jolie's mother, grandmother, and aunt all died from cancer.

According to the National Cancer Institute, women who carry the BRCA1 gene mutation have, on average, a 55–65 percent risk on average of developing breast cancer and a 39 percent risk of developing ovarian cancer. Because of her family history of cancers and the presence of BRCA1, Jolie's doctors estimated that she had an 87 percent risk of breast cancer and a 50 percent risk of ovarian cancer.

In the years following her discovery and full mastectomy, Jolie's chances of developing breast cancer have dropped to under 5 percent. She has also undergone ovarian and fallopian tube removal to reduce her chances of developing ovarian cancer.

Weighing the Decision

While it may not be easy to live with the fact that you or a loved one has cancer, it is wise to take charge and confront health issues directly. To date, scientists have identified more than 200 hereditary cancer-susceptibility syndromes, with the majority of these syndromes detectable only through genetic testing, according to Oncogene.

If you are contemplating genetic testing, speak with your doctor and a genetics counselor before making a final decision. Since genetic testing is only suggested for people at high risk of developing certain cancers, a genetics counselor will help you consider that decision by weighing the risks, benefits, and limitations of testing in your particular situation. For those who do end up requiring genetic testing, a simple blood draw will determine whether you and your family members are at higher risks for certain types of cancer.

Genetic testing provides answers to questions that some people may not want to ask. It comes down to how prepared and proactive you want to be in addressing potential future health issues. Genetic testing may not be for everyone, but by at least allowing medical experts to review your family history, you'll be able to make an informed decision regarding your health and the appropriateness of genetic testing for you and your family.

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