You are here: Home / Featured Article / Part 4

Primary Care Clinicians and the Dilemmas of Genetic Testing

 

Part 4: Challenges Inherent in Information Obtained by Genetic Tests

In general, clinicians have reserved in-depth consultation and patient counseling for difficult therapeutic decisions, and have tended to think of informed consent primarily in the context of treatment. In genetic medicine, however, the most important informed consent discussion is the one that takes place prior to ordering any tests – in the context of diagnosis. Consider some of the challenges that this presents for clinicians:

  1. Genetic information does not affect only the individual receiving the test, but other family members as well. While we have always been able to make inferences about the health status of family members from family medical histories and general medical information, genetic testing makes those inferences considerably more precise, bringing some dramatic medical, ethical and psychological side effects into play. For example, the tape depicts, and a number of studies describe, how family members who do not carry a mutation can experience “survivor guilt”, demonstrating that even a negative genetic test may have adverse psychological consequences.13  

    A related dilemma concerns whether a clinician has the right, or even the duty, to override her/his patient’s wish to keep test results private in order to warn potentially affected family members. As the tape shows, there is disagreement about whether such a duty exists. 

     

     

     

  2. Genetic information can transform how individuals perceive themselves and are perceived by others. Even in the absence of clinical disease, a positive genetic test result has the potential to transform how a person perceives herself and is perceived by her family, employer, and health care provider. Such “reclassification” of course can have important psychological effects. It may also affect one’s chances of getting or keeping a job; one’s chances of being promoted; or one’s access to health insurance or life insurance coverage. Anecdotal evidence suggests that genetic discrimination is an issue, but as of today, there still are no good data on how often such discrimination actually occurs.14  

    Given that comprehensive federal legislation against genetic discrimination has not been passed (as of July 2003), and that state laws vary, patients are still wise to question the consequences of testing. And in the current health care context, where medical information is shared across huge networks, providers offering tests are faced with the dilemma of being unable to ensure privacy and confidentiality for their patients. It is therefore critical for clinicians to speak explicitly with patients about the prospect that their test results might be disclosed. 

     

     

     

  3. Genetic information is essentially probabilistic, making it more complex and more difficult to communicate to patients than other types of medical information. As has been shown in numerous studies, effective communication of risk or probabilistic information to patients in the primary care setting is very challenging.15 Genetic ‘information’ can paradoxically, seem to create more uncertainty than it resolves. This is seen in the program’s first case about BRCA testing. To begin with, there is the phenomenon of incomplete penetrance: even if a person has a mutation associated with a given disease, she will not necessarily have symptoms of that disease. Second, the absence of a mutation does not ensure the absence of disease. Less than 10% of breast and ovarian cancer can be traced to identified inherited mutations, while more than 90% can not be.  

    Another source of uncertainty in genetic illness is variable expressivity. As illustrated in the tape, even when we know for certain that a fetus is destined to develop cystic fibrosis, we do not know how severe the CF will be or at what age it will first manifest. Moreover, inaccuracy of genetic tests, namely false positive and false negative results, add yet another layer of complexity to genetic medicine. As we saw in our CF case, the lack of standardization in laboratory procedures can easily lead to a false negative result. Finally, as Dr. Giardiello explains in the tape, his study demonstrated that clinicians’ lack of familiarity with these tests can, and has led to serious misinterpretation, even when the test results are accurate.16

  4. Since there are few definitive therapies, the clinical uses of genetic information are often subtle. In genetic medicine today, testing is often far ahead of therapeutics. The utility of these tests may lie either in the psychological benefit of ‘knowing’ one’s status or, in some cases, in the preventive strategies that such testing can promote. The former is highly dependent on individual preferences and coping styles, which need to be carefully explored. The latter depends on a number of complex interacting factors as described by Evans.17 In particular, each of the following factors tends to increase the utility of genetic testing.
    1. The test is highly predictive
    2. The disorder involved is serious
    3. The illness is not easily detected by standard screening or surveillance
    4. The illness is not easily treated once manifest, and
    5. Effective preventive and/or screening measures exist, but are too costly or difficult to recommend to the entire population.

For example, according to Evans, a predictive genetic test for hypertension would not have a high utility, as this condition is easily screened, effectively treated once manifest, and the preventive strategies are relatively inexpensive, and probably beneficial for the entire population – not just for those at high risk. Therefore, population-based genetic testing would probably add little to the overall management of this condition.

Next: The Process of Facilitating Truly Informed Consent >>
Or: Download Complete Article >>