Predictive genetic testing and cancer

Predictive genetic testing may help identify people who are at an increased risk for developing certain types of cancer. While this type of testing may indicate the absence or presence of a gene thought to be associated with a specific cancer (for example, the BRCA1 gene and one form of breast cancer), testing also carries many limitations and risks. Before undergoing genetic testing, you need to fully understand the process and its implications. here are some items to consider.

An accurate test may produce a positive, negative, or ambiguous result, but it cannot guarantee that a person will or will not develop cancer. As thorough a knowledge as possible of family history is perhaps the most important part of any genetic test. However, people with no information on their potential cancer ancestry can still learn some things from genetic testing. In the latter case, a person's pertinent genetic makeup can be compared to others in the general population or with similar ethnic ancestry.

Many experts recommend undergoing genetic testing only when a pedigree analysis suggests the presence of an inherited cancer syndrome for which a specific mutation has been identified. Other guidelines suggest that genetic testing should be pursued only when the test will impact future medical care and decisions.

Besides family history, another important element of genetic testing is the assistance of a genetic counselor. Generally, your family doctor has neither the knowledge nor the time to provide all the assistance you may need. Your doctor may, however, be able to help you find a counselor and arrange for testing and support.

Marie Godfrey, PhD 

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