The management of ancillary information from PGx testing raises many issues for both physicians and patients. From the patient perspective, questions arise as to whether patients should be informed about ancillary information prior to testing, their desire to learn of the risk information, and what factors influence these decisions. In addition, the potential of ancillary findings unrelated to the drug treatment question for which testing is performed may impact patient and physician interest in these tests. Physician enthusiasm for PGx testing for smoking cessation treatments has been reported to be lessened by the potential for ancillary risk information, especially for stigmatizing conditions.23–25
We found this was not the case for the general public; interest in PGx testing remained high after respondents were informed about the potential for ancillary information. The high interest suggests that the public is more interested in PGx testing than their physicians might anticipate and do not consider ancillary information to be a major drawback of testing, and may, in some cases, consider it an added benefit.
Most respondents felt physicians should inform patients about potential ancillary information prior to PGx testing. The strong interest in being informed prior to testing is in line with the increasingly active role of patients in the decision-making process for medical care.26
However, disclosure of ancillary information leaves uncertainties with respect to informed consent standards of liability. For example, what types of ancillary information should the patient be informed about prior to their decision to undergo PGx testing – any type of ancillary information or only that for diseases with available interventions?
If ancillary risk information for untreatable or potentially stigmatizing conditions could be revealed by a PGx test, such as Alzheimer’s disease5–9
or mental illness,11
the test may be considered “high” risk requiring a detailed consent process.4, 27
It is not only the existence of ancillary information, but the characteristics of that information that would dictate the appropriate level of consent.28
Furthermore, in addition to discussing the potential of the ancillary information prior to making a decision to undergo PGx testing, it may be prudent to also discuss the potential benefits and harms of learning of the information. For example, potential clinical follow-up of ancillary risks may lead to costly and/or potentially risky interventions.29–31
In research settings, some scholars have recommended that the potential for ancillary information should be disclosed to research subjects during the informed consent.32
While informed consent is standard practice for most clinical research studies, it is not routinely obtained for PGx testing in general,33
particularly for tests considered standard of care,34, 35
and therefore, would result in a major change in practice.
Although most respondents wished to know about ancillary information prior to testing, interest in learning of the information varied between respondents. Some of this variability may be attributed to differences in interpretation of the descriptors used in the survey (serious versus moderate risk), or treatable. In addition, our presentation of risk (i.e., low) could have influenced respondents’ interest given that different ways of presenting risk (numerical risks such as relative risk versus descriptive risks) can impact response and understanding.36
As it was not feasible to ask about their interest in ancillary information based on a combination of factors that would be disclosed in an actual clinical situation (e.g., level of uncertainty and
availability of treatment and
disease characteristics), we might expect even greater differences in attitudinal responses. Such limited information scenarios may account for differences between higher expressed levels of interest and lower rates of actual test uptake37, 38
as well as disparities in physician and public attitudes regarding ancillary information.
Not surprisingly, respondents were most interested in learning of risks for serious but treatable diseases and least interested in learning of uncertain risks. College graduates were the only group who were less likely to want to learn of their risk for serious but untreatable diseases. Two possible reasons that may account for this finding are fear of discrimination or desire to avoid potential anxiety and stress. A recent study of personalized genomic risk assessments reported that 82% would want to know of risks for serious diseases that could not be prevented.39
Women were less likely to want to learn of ancillary risks for several scenarios. These findings comport with previous work suggesting that women have greater dread of risks,40
and specifically, greater concerns about personalized genomic risk assessments.39
Positive carrier test results for women have also been shown to result in greater anxiety than for positive male carriers,41, 42
perhaps due to the greater perceived value and benefits of testing for women given the implications for reproductive decision-making.43
The trend toward not
wanting to learn of certain types of ancillary risk appears in contrast with the understanding that women are typically active health information seekers.44
Women pre-dominantly make most of the health care decisions for themselves and family members,45
based on a combination of personal values, beliefs, and past experiences.46
Perceived lack of control has been associated with failure to partake in some beneficial health behaviors,47
but this reasoning does not explain our finding that women were less interested in genomic-based risk for treatable diseases (mild or serious) compared to untreatable. Few studies have examined interest or experience in genetic risk information for serious, non-treatable disease. A study involving APOE genotyping for Alzheimer’s risk in individuals with a family history of Alzheimer reported that a high proportion of interested participants were female and well-educated,48
suggesting that treatability may only be one criterion considered when deciding to learn of such risk information.
As PGx testing progresses in clinical practice, it is essential to consider the consequences of informational side effects for the patient and their care. The issue of ancillary or incidental findings, particularly in genome research,49
has garnered recent attention due to the volumes of data that can be generated in a single study from sequencing or other technology platforms and concerns about how the data should be appropriately managed.50–52
The strong interest in learning about ancillary information is well-aligned with the public’s desire to be informed about benefits and risks of testing, thus empowering them with the autonomy to make an informed decision about testing. Awareness of the potential for ancillary information may be considered material to patients’ decisions about PGx testing. However, despite their interest, from an ethical and legal perspective, it is still uncertain whether all types of ancillary information should be disclosed. Thus, further study is warranted to examine the types of ancillary information that should be disclosed to patients during discussion of PGx testing, whether patients choose to learn of the information and the benefits and harms associated with learning it, and the delivery of ancillary information.