Knowing something is almost always better than not knowing. Cancer will impact one in three people over their lifetime; a statistic that suggests that contacting the deadly disease is a matter of random chance. Knowledge that one is in the “more likely to get” column can be seen as good news, resulting in closer monitoring and additional testing that could potentially lead to earlier discovery and therefore an increased chance of treatment and survival.
Most cancer risks are directly related to personal behaviors such as using tobacco or over exposure to the sun or other cancer-causing substances and activities. Family cancer syndrome (inherited cancer) can occur when inherited gene mutations that are passed from generation to generation increase the odds of contracting the disease. Only about 5% to 10% of all cancers are thought to result directly from gene mutations inherited from a parent.
Family history of the same type of cancer; cancers developing at earlier ages; multiple family members contacting identical or rare cancers or cancers experienced in multiple generations are some cancers thought to be indicative of family cancer syndrome. Cancer occurrence within close relations is more cause for concern than those in distant relationships. For some rare cancers, the risk of a family cancer syndrome is relatively high with even one case. Some types of cancers have no known mutations linked to an increased risk and others may have known mutations, but no way to test for them.
Genetic testing can be performed by either a blood or cheek swab sample and do not detect whether a person has cancer; testing indicates whether a person carries a change in one of their genes which can increase cancer risk. Most people will not benefit from genetic testing for cancer, but those who have a strong indication of family gene mutations may be able to take actions that lower the risk of the disease.
BRCA1 and BRCA2 are the most common genes involved in hereditary breast and ovarian cancers and a positive connection to these genes can also indicate a higher risk for other cancers, but nearly 85% of breast cancers occur in women who have no family history of the disease. No genetic test can determine whether a person will develop cancer with certainty.
The results of genetic testing can be beneficial in making medical decisions for cancer treatment, additional screening and prevention. Selecting the correct test and interpreting the results accurately can be complex, and the decision to have the test may impact personal relationships with other family members. For these reasons, the decision to undergo genetic testing is a very personal one, and one that should be made after considering all unique circumstances.