Cancer Genetic Testing
What is genetic testing?
Genetic testing is the process of using medical tests to look for changes (mutations) in a person’s genes or chromosomes. Hundreds of different genetic tests are used today, and more are being developed.
- Genetic testing helps predict the likelihood that a person will develop a disease, including some types of cancer.
- Genetic testing is a personal decision with many factors to consider.
- Anyone who decides to undergo genetic testing should receive genetic counseling before and after the test is performed.
Genetic testing is the analysis of genes, chromosomes, or proteins to help predict the risk of disease, identify carriers (individuals who do not have the disease but have a copy of the disease gene) of disease, diagnose disease, or determine the likely course of a disease. More than 900 genetic tests are available for many different diseases, including breast, ovarian, colon, thyroid, and other cancers.
Genetic testing for cancer risk is sometimes called predictive testing, which means that it can help predict the likelihood that an individual will develop cancer in his or her lifetime. No genetic test can report with 100% certainty that a person will develop cancer, but the tests can tell a person if he or she has a higher risk of developing cancer than the general population. Not everyone with a cancer-predisposition gene will develop cancer. For example, a woman with a 75% chance of developing breast cancer may remain healthy, while a woman with a 25% chance of developing breast cancer may eventually develop cancer.
The following factors suggest that a person may be at risk for developing a hereditary cancer:
Family history of cancer: Three or more relatives on the same side of the family with the same or related forms of cancer
Early onset: Two or more relatives diagnosed with cancer at an early age
Multiple sites: Two or more types of cancer occurring in the same relative
we recommends that genetic testing be offered in the following situations:
-The person has an individual or family history that suggests a genetic cause of cancer
-The test for the genetic condition can be adequately interpreted
-The results of the genetic test will help with the diagnosis, treatment, and/or management of the patient and family members at risk for cancer
Questions to ask yourself about genetic testing
Before being tested, be sure you have a complete understanding of the risks of testing and your reasons for wanting a test. It is also helpful to think about how you will cope with the results of the test. The following are some factors to consider in your decision making:
-Do I have a family history of cancer, or have I developed cancer at an earlier-than-average age?
-How will I interpret the results of genetic testing? Who will assist me in using this information?
-Will knowing the test results affect my medical care or the medical care of my family?
-If a genetic condition is detected, are there steps I can take to lower my risk?
A genetic counselor can help address these issues. Genetic counselors are professionals specially trained to advise people about the risks and benefits of genetic testing and can help people through the process of testing and interpreting the results.