Genetic Testing for Breast and Ovarian Cancer Susceptibility
Once it has been determined that a client is at increased risk for breast and ovarian cancer, the client should be given an opportunity to discuss the benefits, risks, and limitations of genetic testing. The client needs to understand that this type of genetic testing is inherently a family experience.[5,6,7,50,51,52] Not only will the results have implications for other family members, but also the ability to do testing in an effective manner depends heavily on the willingness of one or more family members who have already been diagnosed with cancer to undergo the testing first. In some families, the testing of an affected family member may not be possible because the affected family member has already died. In other families, the affected member may be living but unwilling or uninterested in being tested. This may lead to impaired family communication and altered family relationships.[4,50,51,52]
One of the most frequently mentioned benefits of genetic testing for breast and ovarian cancer susceptibility is the opportunity to learn if one has the potential to transmit genetic mutations to one's offspring.[4,7,53] Another possible benefit is the ability to learn one's own risk for developing hereditary breast and ovarian cancer. Relief from the uncertainty associated with not knowing one's own genetic status has the potential to dramatically impact individual and family well-being. An additional benefit of genetic testing for breast and ovarian cancer susceptibility is the ability to use the information obtained through genetic testing to individualize cancer risk management and promote risk reduction behaviors, such as lifestyle changes.[54,55]
Potential risks of genetic testing for breast and ovarian cancer susceptibility include: psychological distress, potential loss of privacy, change in family dynamics, potential for genetic discrimination, increased medical expenses due to additional screening and surveillance, and a false sense of security.[28,31,52,54,56,57,58,59,60] Findings from a recent review of the literature concerning the psychological implications of genetic testing suggest that the severity of psychological risks posed by genetic testing may not be as great as was originally anticipated. However, certain subgroups of individuals may be more vulnerable to adverse effects.[55,56,62] Feelings of guilt may be experienced by both carriers and non-carriers of the BRCA mutation. Parents, in particular, may feel guilty about the possibility of passing the mutation onto their children. Non-carriers may experience "survivor guilt." Individuals found to be carriers of a BRCA mutation have reported that informing their relatives of the "bad news" is stressful and burdensome.[2,7] Many families continue to fear genetic discrimination,[26,53,54] even though there have been no well-documented cases that demonstrate discrimination based on the results of a genetic test for breast and ovarian cancer susceptibility.
Genetic testing for breast and ovarian cancer susceptibility has a number of limitations. One limitation is that the results indicate the probability, not the certainty, of developing cancer. Not all individuals who test positive for BRCA mutations develop cancer. Another limitation is that genetic testing may miss a BRCA mutation that actually exists in the family, especially if the mutation is a large deletion. DNA sequencing may fail to pick up large deletions because the presence of a normal copy of the gene makes the result appear normal. A third limitation of genetic testing for breast and ovarian cancer susceptibility is that the family may have a mutation in a gene other than the breast and ovarian cancer susceptibility genes that have already been identified. A fourth limitation is that a negative result is fully informative only if the mutation has already been identified in a family member. Finally, to date, medical interventions have not been proved to prevent the development of breast and ovarian cancer.
In April 2003, the American Society of Clinical Oncology published the following update on their policy statement concerning genetic testing for cancer susceptibility.
"ASCO recommends that genetic testing be offered when (1) the individual has personal or family history features suggestive of a genetic cancer susceptibility condition, (2) the test can be adequately interpreted, and (3) the results will aid in diagnosis or influence the medical or surgical management of the patient or family members at hereditary risk of cancer. ASCO recommends that genetic testing only be done in the setting of pre- and post-test counseling, which should include discussion of possible risks and benefits of cancer early detection and prevention modalities."
If a client has no family history of breast or ovarian cancer, the client's risk of developing breast cancer is similar to that of an average-risk individual, so there would be little justification for the client undergoing BRCA testing. Moreover, testing could cause harm through false reassurance and its consequences. The client could end up believing that her risk of breast cancer is lower than average because her results were negative, when in fact, her risk would stay the same because she was not expected to have a BRCA mutation.
J Midwifery Womens Health. 2004;49(3) © 2004 Elsevier Science, Inc.
Cite this: Genetic Testing for Breast and Ovarian Cancer Susceptibility: A Family Experience - Medscape - May 01, 2004.