Barriers for integrating personalized medicine into clinical practice: a qualitative analysis

Non-Invasive Prenatal Testing (NIPT): Reliability, Challenges, and Future Directions

Non-invasive prenatal testing was first discovered in 1988; it was primarily thought to be able to detect common aneuploidies, such as Patau syndrome (T13), Edward Syndrome (T18), and Down syndrome (T21). It comprises a simple technique involving the analysis of cell-free foetal DNA (cffDNA) obtained through maternal serum, using advances in next-generation sequencing. NIPT has shown promise as a simple and low-risk screening test, leading various governments and private organizations worldwide to dedicate significant resources towards its integration into national healthcare initiatives as well as the formation of consortia and research studies aimed at standardizing its implementation. This article aims to review the reliability of NIPT while discussing the current challenges prevalent among different communities worldwide.

Engineering considerations of iPSC-based personalized medicine

Personalized medicine aims to provide tailored medical treatment that considers the clinical, genetic, and environmental characteristics of patients. iPSCs have attracted considerable attention in the field of personalized medicine; however, the inherent limitations of iPSCs prevent their widespread use in clinical applications. That is, it would be important to develop notable engineering strategies to overcome the current limitations of iPSCs. Such engineering approaches could lead to significant advances in iPSC-based personalized therapy by offering innovative solutions to existing challenges, from iPSC preparation to clinical applications. In this review, we summarize how engineering strategies have been used to advance iPSC-based personalized medicine by categorizing the development process into three distinctive steps: 1) the production of therapeutic iPSCs; 2) engineering of therapeutic iPSCs; and 3) clinical applications of engineered iPSCs. Specifically, we focus on engineering strategies and their implications for each step in the development of iPSC-based personalized medicine.

Central resources of variant discovery and annotation and its role in precision medicine

Rapid technological advancement in high-throughput genomics, microarray, and deep sequencing technologies has accelerated the possibility of more complex precision medicine research using large amounts of heterogeneous health-related data from patients, including genomic variants. Genomic variants can be identified and annotated based on the reference human genome either within the sequence as a whole or in a putative functional genomic element. The American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) mutually created standards and guidelines for the appraisal of proof to expand consistency and straightforwardness in clinical variation interpretations. Various efforts toward precision medicine have been facilitated by many national and international public databases that classify and annotate genomic variation. In the present study, several resources are highlighted with recognition and data spreading of clinically important genetic variations.

Representations of personalised medicine in family medicine: a qualitative analysis

Background

The promise of personalised medicine (PM) to transform healthcare has sparked great enthusiasm in the last years. Yet, its lack of consensus around the nature and scope of the concept has ended in terminological confusion amongst the users in primary care. We aimed to investigate the perceptions of doctors and their patients in response to this evolving concept. This present article focuses on the general understanding of personalised medicine, underlining the confusion over the concept.

Methods

Semi-structured comprehensive interviews were conducted with 10 general practitioners (GPs) and 10 of their patients. The purposive sampling took into account the doctor’s age, sex, and place of practice (rural/urban); each doctor recruited one patient of the same age and sex. Each interview began with the same open-ended question about the participant’s knowledge of the topic, after which a working definition was provided to continue the discussion. Using the grounded theory method, the analysis consisted of open coding, axial coding and selective coding.

Results

From our present analysis focusing on the general understanding of PM, three main themes representing the concept emerged. The first two representations being “centred on the person as a whole” and “focused on alternative and complementary methods”, in which the therapeutic relationship was stated as key. The third theme “medicine open to innovation” involved the few participants who had a good understanding of the concept and could associate personalised medicine with genomics. For those who value therapeutic relationship, the risks of accepting innovation could result in “fast-food” medicine and interpersonal barriers.

Discussion

PM is predominantly unfamiliar in family medicine. It is misinterpreted as a holistic or integrative type of medicine. This semantic confusion probably lies in the choice of the label “personalised” or from the lack of a uniform definition for the term.

Limited Genomics Training Among Physicians Remains a Barrier to Genomics-Based Implementation of Precision Medicine

The field of precision medicine has undergone significant growth over the past 10 years. Despite increasing applications of clinical genetic and genomic testing, studies consistently report limited knowledge of genetics and genomics among healthcare providers. This study explored barriers to the implementation of precision medicine by surveying physicians working in a large academic medical center. We assessed prior training in genetics, use of genetic testing in the clinic, desire for additional resources in genetics and genomic medicine and perceived barriers to successful integration of precision medicine. Only 20% of respondents reported moderate or extensive training in genetics. Physicians with limited or no training in genetics were less likely to have ordered a genetic test for any purpose. Furthermore, 41% of physicians responded that their lack of training identifying appropriate genetic tests and how to interpret genetic testing results was the most significant barrier to ordering genetic testing for their patients. These findings suggest that future efforts to realize the promise of precision medicine should focus on the integration of training programs for non-genetics trained healthcare providers.

Understanding barriers to the introduction of precision medicine in non-small cell lung cancer: a qualitative interview study

Background: While treatments targeting genetic mutations and alterations in non-small cell lung cancer (NSCLC) have been available since 2010, the adoption of such examples of precision medicine into clinical practice has historically been slow. This means that patients with NSCLC may not have received life improving and extending treatments which should have been available to them. The purpose of this qualitative interview study was to identify the barriers to the provision of examples of precision medicine for NSCLC. Methods: This study used semi-structured telephone interviews with clinicians, test providers and service commissioners to identify the perceived barriers to providing historical, current, and future examples of precision medicine in NSCLC. Participants were identified through mailing list advertisements and snowball sampling. The qualitative data was analysed using a framework analysis. Results: Interviews were conducted with 11 participants including: five oncologists; three pathologists; two clinical geneticists; and one service commissioner. A total of 17 barriers to the introduction of precision medicine for NSCLC were identified and these were grouped into five themes: the regulation of precision medicine and tests; the commissioning and reimbursement of tests and the testing process; the complexity of the logistics around providing tests; centralisation or localisation of test provision; and opinions about future developments in precision medicine for NSCLC. Conclusions: A number of barriers exist to the introduction of precision medicine in NSCLC. Addressing these barriers may improve access to novel life improving and extending treatments for patients.

Barriers and strategies to integrate medical genetics and primary care in underserved populations: a scoping review

Despite clinical and technological advances, serious gaps remain in delivering genetic services due to disparities in workforce distribution and lack of coverage for genetic testing and counseling. Genetic services delivery, particularly in medically underserved populations, may rely heavily on primary care providers (PCPs). This study aims to identify barriers to integrating genetic services and primary care, and strategies to support integration, by conducting a scoping review. Literature synthesis found barriers most frequently cited by PCPs including insufficient knowledge about genetics and risk assessment, lack of access to geneticists, and insufficient time to address these challenges. Telegenetics, patient-centered care, and learning communities are strategies to overcome these barriers. Telegenetics supplements face-to-face clinics by providing remote access to genetic services. It may also be used for physician consultations and education. Patient-centered care allows providers, families, and patients to coordinate services and resources. Access to expert information provides a critical resource for PCPs. Learning communities may represent a mechanism that facilitates information exchange and knowledge sharing among different providers. As PCPs often play a crucial role caring for patients with genetic disorders in underserved areas, barriers to primary care-medical genetics integration must be addressed to improve access. Strategies, such as telegenetics, promotion of evidence-based guidelines, point-of-care risk assessment tools, tailored education in genetics-related topics, and other system-level strategies, will facilitate better genetics and primary care integration, which in turn, may improve genetic service delivery to patients residing in underserved communities.

Noninvasive biomarkers for prediction and diagnosis of heart transplantation rejection

For most patients with end-stage heart failure, heart transplantation is the treatment of choice. Allograft rejection is one of the major post-transplantation complications affecting graft outcome and survival. Recent advancements in science and technology offer an opportunity to integrate genomic and other omics-based biomarkers into clinical practice, facilitating noninvasive evaluation of allograft for diagnostic and prognostic purposes. Omics, including gene expression profiling (GEP) of blood immune cell components and donor-derived cell-free DNA (dd-cfDNA) are of special interest to researchers. Several studies have investigated levels of dd-cfDNA and miroRNAs in blood as potential markers for early detection of allograft rejection. One of the achievements in the field of transcriptomics is AlloMap, GEP of peripheral blood mononuclear cells (PBMC), which can identify 11 differentially expressed genes and help with detection of moderate and severe acute cellular rejection in stable heart transplant recipients. In recent years, the utilization of GEP of PBMC for identifying differentially expressed genes to diagnose acute antibody-mediated rejection and cardiac allograft vasculopathy has yielded promising results. Advancements in the field of metabolomics and proteomics as well as their potential implications have been further discussed in this paper.

Implementing Interventions with Varying Marginal Cost-Effectiveness: An Application in Precision Medicine

Purpose. A range of barriers may constrain the effective implementation of strategies to deliver precision medicine. If the marginal costs and consequences of precision medicine vary at different levels of implementation, then such variation will have an impact on relative cost-effectiveness. This study aimed to illustrate the importance and quantify the impact of varying marginal costs and benefits on the value of implementation for a case study in precision medicine. Methods. An existing method to calculate the value of implementation was adapted to allow marginal costs and consequences of introducing precision medicine into practice to vary across differing levels of implementation. This illustrative analysis used a case study based on a published decision-analytic model-based cost-effectiveness analysis of a 70-gene recurrence score (MammaPrint) for breast cancer. The impact of allowing for varying costs and benefits for the value of the precision medicine and of implementation strategies was illustrated graphically and numerically in both static and dynamic forms. Results. The increasing returns to scale exhibited by introducing this specific example of precision medicine mean that a minimum level of implementation (51%) is required for using the 70-gene recurrence score to be cost-effective at a defined threshold of €20,000 per quality-adjusted life year. The observed variation in net monetary benefit implies that the value of implementation strategies was dependent on the initial and ending levels of implementation in addition to the magnitude of the increase in patients receiving the 70-gene recurrence score. In dynamic models, incremental losses caused by low implementation accrue over time unless implementation is improved. Conclusions. Poor implementation of approaches to deliver precision medicine, identified to be cost-effective using decision-analytic model-based cost-effectiveness analysis, can have a significant economic impact on health systems. Developing and evaluating the economic impact of strategies to improve the implementation of precision medicine will potentially realize the more cost-effective use of health care budgets.

Evidence to Support Inclusion of Pharmacogenetic Biomarkers in Randomised Controlled Trials

Pharmacogenetics and biomarkers are becoming normalised as important technologies to improve drug efficacy rates, reduce the incidence of adverse drug reactions, and make informed choices for targeted therapies. However, their wider clinical implementation has been limited by a lack of robust evidence. Suitable evidence is required before a biomarker’s clinical use, and also before its use in a clinical trial. We have undertaken a review of five pharmacogenetic biomarker-guided randomised controlled trials (RCTs) and evaluated the evidence used by these trials to justify biomarker inclusion. We assessed and quantified the evidence cited in published rationale papers, or where these were not available, obtained protocols from trial authors. Very different levels of evidence were provided by the trials. We used these observations to write recommendations for future justifications of biomarker use in RCTs and encourage regulatory authorities to write clear guidelines.

Accounting for Capacity Constraints in Economic Evaluations of Precision Medicine: A Systematic Review

BACKGROUND AND OBJECTIVE

Precision (stratified or personalised) medicine is underpinned by the premise that it is feasible to identify known heterogeneity using a specific test or algorithm in patient populations and to use this information to guide patient care to improve health and well-being. This study aimed to understand if, and how, previous economic evaluations of precision medicine had taken account of the impact of capacity constraints.

METHODS

A meta-review was conducted of published systematic reviews of economic evaluations of precision medicine (test-treat interventions) and individual studies included in these reviews. Due to the volume of studies identified, a sample of papers published from 2007 to 2015 was collated. A narrative analysis identified whether potential capacity constraints were discussed qualitatively in the studies and, if relevant, which quantitative methods were used to account for capacity constraints.

RESULTS

A total of 45 systematic reviews of economic evaluations of precision medicine were identified, from which 222 studies focusing on test-treat interventions, published between 2007 and 2015, were extracted. Of these studies, 33 (15%) qualitatively discussed the potential impact of capacity constraints, including budget constraints; quality of tests and the testing process; ease of use of tests in clinical practice; and decision uncertainty. Quantitative methods (nine studies) to account for capacity constraints included static methods such as capturing inefficiencies in trials or models and sensitivity analysis around model parameters; and dynamic methods, which allow the impact of capacity constraints on cost effectiveness to change over time.

CONCLUSIONS

Understanding the cost effectiveness of precision medicine is necessary, but not sufficient, evidence for its successful implementation. There are currently few examples of evaluations that have quantified the impact of capacity constraints, which suggests an area of focus for future research.

Person Centered Care and Personalized Medicine: Irreconcilable Opposites or Potential Companions?

In contrast to standardized guidelines, personalized medicine and person centered care are two notions that have recently developed and are aspiring for more individualized health care for each single patient. While having a similar drive toward individualized care, their sources are markedly different. While personalized medicine stems from a biomedical framework, person centered care originates from a caring perspective, and a wish for a more holistic view of patients. It is unclear to what extent these two concepts can be combined or if they conflict at fundamental or pragmatic levels. This paper reviews existing literature in both medicine and related philosophy to analyze closer the meaning of the two notions, and to explore the extent to which they overlap or oppose each other, in theory or in practice, in particular regarding ethical assumptions and their respective practical implications.

A theory-informed systematic review of clinicians' genetic testing practices

This systematic literature review investigates factors impacting on clinicians' decisions to offer genetic tests in their practice, and maps them to a theoretical behaviour change framework. Better understanding of these factors will inform the design of effective interventions to integrate genomics tests into clinical care. We conducted a narrative synthesis of empirical research of medical specialists' perspectives on and experiences of offering genetic tests to their patients. This review was based upon the PRISMA statement and guidelines for reviewing qualitative research. Four electronic data sources were searched-MEDLINE, EMBASE, CINAHL, PubMed. Studies were independently assessed by two authors. Content analysis was applied to map the findings of included studies to a framework validated for behaviour and implementation research, the Theoretical Domains Framework (TDF). The TDF describes 14 factors known to influence behaviour and has been applied in diverse clinical settings to understand and/or modify health professional behaviour. Thirty-four studies published in 39 articles met inclusion and quality criteria. Most studies were published after 2011 (54%), Northern American (82%), quantitative in design (68%) and addressed familial cancer genetic tests (53%). Of the 14 TDF factors, 13 were identified. The three most common factors were: Environmental Context and Resources (n = 33), Beliefs about Consequences (n = 26), and Knowledge (n = 23). To support the adoption of genomic tests beyond specialist services, nuanced interventions targeting considerations beyond clinician education are needed. For instance, interventions addressing organisational constraints which may restrict clinicians' ability to offer genomic tests are required alongside those targeting factors intrinsic to the clinician.

How Primary Care Providers Talk to Patients about Genome Sequencing Results: Risk, Rationale, and Recommendation

BACKGROUND

Genomics will play an increasingly prominent role in clinical medicine.

OBJECTIVE

To describe how primary care physicians (PCPs) discuss and make clinical recommendations about genome sequencing results.

DESIGN

Qualitative analysis.

PARTICIPANTS

PCPs and their generally healthy patients undergoing genome sequencing.

APPROACH

Patients received clinical genome reports that included four categories of results: monogenic disease risk variants (if present), carrier status, five pharmacogenetics results, and polygenic risk estimates for eight cardiometabolic traits. Patients' office visits with their PCPs were audio-recorded, and summative content analysis was used to describe how PCPs discussed genomic results.

KEY RESULTS

For each genomic result discussed in 48 PCP-patient visits, we identified a "take-home" message (recommendation), categorized as continuing current management, further treatment, further evaluation, behavior change, remembering for future care, or sharing with family members. We analyzed how PCPs came to each recommendation by identifying 1) how they described the risk or importance of the given result and 2) the rationale they gave for translating that risk into a specific recommendation. Quantitative analysis showed that continuing current management was the most commonly coded recommendation across results overall (492/749, 66%) and for each individual result type except monogenic disease risk results. Pharmacogenetics was the most common result type to prompt a recommendation to remember for future care (94/119, 79%); carrier status was the most common type prompting a recommendation to share with family members (45/54, 83%); and polygenic results were the most common type prompting a behavior change recommendation (55/58, 95%). One-fifth of recommendation codes associated with monogenic results were for further evaluation (6/24, 25%). Rationales for these recommendations included patient context, family context, and scientific/clinical limitations of sequencing.

CONCLUSIONS

PCPs distinguish substantive differences among categories of genome sequencing results and use clinical judgment to justify continuing current management in generally healthy patients with genomic results.

The clinical impact of using complex molecular profiling strategies in routine oncology practice

Molecular profiling and functional assessment of signalling pathways of advanced solid tumours are becoming increasingly available. However, their clinical utility in guiding patients’ treatment remains unknown. Here, we assessed whether molecular profiling helps physicians in therapeutic decision making by analysing the molecular profiles of 1057 advanced cancer patient samples after failing at least one standard of care treatment using a combination of next-generation sequencing (NGS), immunohistochemistry (IHC) and other specific tests. The resulting information was interpreted and personalized treatments for each patient were suggested. Our data showed that NGS alone provided the oncologist with useful information in 10–50% of cases (depending on cancer type), whereas the addition of IHC/other tests increased extensively the usefulness of the information provided. Using internet surveys, we investigated how therapy recommendations influenced treatment choice of the oncologist. For patients who were still alive after the provision of the molecular information (76.8%), 60.4% of their oncologists followed report recommendations. Most treatment decisions (93.4%) were made based on the combination of NGS and IHC/other tests, and an approved drug- rather than clinical trial enrolment- was the main treatment choice. Most common reasons given by physicians to explain the non-adherence to recommendations were drug availability and cost, which remain barriers to personalised precision medicine. Finally, we observed that 27% of patients treated with the suggested therapies had an overall survival > 12 months. Our study demonstrates that the combination of NGS and IHC/other tests provides the most useful information in aiding treatment decisions by oncologists in routine clinical practice.

Understanding barriers to the introduction of precision medicines in non-small cell lung cancer: A qualitative interview protocol

Background: While precision medicines targeting genetic mutations and alterations in non-small cell lung cancer (NSCLC) have been available since 2010, their adoption into clinical practice has been slow. Evidence suggests that a number of barriers, such as insufficient clinician knowledge, a need for training of test providers, or a lack of specific clinical guidelines, may slow the implementation of precision in general. However, little attention has been given to the barriers to providing precision medicines in NSCLC. The purpose of this protocol is to outline the design for a qualitative interview study to identify the barriers and facilitators to the provision of precision medicines for NSCLC. Methods: This study will use semi-structured interviews with clinicians (n=10), test providers (n=10), and service commissioners (n=10) to identify the perceived barriers and facilitators to providing historical, current, and future precision medicines in NSCLC. Participants will be identified through mailing list advertisements and snowball sampling. Recruitment will continue until data saturation, indicated by no new themes arising from the data. Interviews will be conducted by telephone to facilitate geographical diversity. The qualitative data will be analysed using a framework analysis with themes anticipated to relate to; relevant barriers to providing precision medicines, the impact of different barriers on medicine provision, changes in the ability to provide precision medicines over time, and strategies to facilitate the provision of precision medicines. Ethics: This study has been approved by the University of Manchester Proportionate Review Research Ethics Committee (Reference number: 2017-1885-3619). Written consent will be obtained from all participants. Conclusion: This study is the first to explore the barriers and facilitators to providing precision medicines for NSCLC in the English NHS. The findings will inform strategies to improve the implementation of future precision medicines. These findings will be disseminated in peer-reviewed publications and national and international conferences.

Point-of-care companion diagnostic tests for personalizing psychiatric medications: fulfilling an unmet clinical need

Over the last decade stable isotope-labeled substrates have been used as probes for rapid, point-of-care, non-invasive and user-friendly phenotype breath tests to evaluate activity of drug metabolizing enzymes. These diagnostic breath tests can potentially be used as companion diagnostics by physicians to personalize medications, especially psychiatric drugs with narrow therapeutic windows, to monitor the progress of disease severity, medication efficacy and to study in vivo the pharmacokinetics of xenobiotics. Several genotype tests have been approved by the FDA over the last 15 years for both cytochrome P450 2D6 and 2C19 enzymes, however they have not been cleared for use in personalizing medications since they fall woefully short in identifying all non-responders to drugs, especially for the CYP450 enzymes. CYP2D6 and CYP2C19 are among the most extensively studied drug metabolizing enzymes, involved in the metabolism of approximately 30% of FDA-approved drugs in clinical use, associated with large individual differences in medication efficacy or tolerability essentially due to phenoconversion. The development and commercialization via FDA approval of the non-invasive, rapid (<60 min), in vivo, phenotype diagnostic breath tests to evaluate polymorphic CYP2D6 and CYP2C19 enzyme activity by measuring exhaled ¹³CO₂ as a biomarker in breath will effectively resolve the currently unmet clinical need for individualized psychiatric drug therapy. Clinicians could personalize treatment options for patients based on the CYP2D6 and CYP2C19 phenotype by selecting the optimal medication at the right initial and subsequent maintenance dose for the desired clinical outcome (i.e. greatest efficacy and minimal side effects).

'Someday it will be the norm': physician perspectives on the utility of genome sequencing for patient care in the MedSeq Project

AIM

To describe practicing physicians' perceived clinical utility of genome sequencing.

MATERIALS & METHODS

We conducted a mixed-methods analysis of data from 18 primary care physicians and cardiologists in a study of the clinical integration of whole-genome sequencing. Physicians underwent brief genomics continuing medical education before completing surveys and semi-structured interviews.

RESULTS

Physicians described sequencing as currently lacking clinical utility because of its uncertain interpretation and limited impact on clinical decision-making, but they expressed the idea that its clinical integration was inevitable. Potential clinical uses for sequencing included complementing other clinical information, risk stratification, motivating patient behavior change and pharmacogenetics.

CONCLUSION

Physicians given genomics continuing medical education use the language of both evidence-based and personalized medicine in describing the utility of genome-wide testing in patient care.

Do physicians think genomic medicine will be useful for patient care?

Significant technological improvements over the last decade have led to a vast expansion in the understanding of the genomic architecture of human disease. However, the use of genomic information, so-called genomic medicine, in routine clinical care, has been slow in comparison to the growth in genomic discovery. The uptake of genomic technology into clinical practice will depend on physicians' perspectives of its utility in patient care. We review recent literature addressing physician attitudes regarding the usefulness and limitations of genomic testing. We conclude by proposing research areas to better understand the role physicians will play in the uptake of genomic information into clinical medicine.

Personalized medicine, availability, and group disparity: an inquiry into how physicians perceive and rate the elements and barriers of personalized medicine

BACKGROUND

The success of personalized medicine depends on factors influencing the availability and implementation of its new tools to individualize clinical care. However, little is known about physicians' views of the availability of personalized medicine across racial/ethnic groups and the relationship between perceived availability and clinical implementation. This study examines physicians' perceptions of key elements/tools and potential barriers to personalized medicine in connection with their perceptions of the availability of the latter across subpopulations.

METHODS

Study subjects consisted of physicians recruited from Cincinnati Children's Hospital Medical Center and UC Health. An electronic survey conducted from September 2012 to November 2012 recruited 104 physicians. Wilcoxon rank sum analysis compared groups.

RESULTS

Physicians were divided about whether personalized medicine contributes to health equality, as 37.4% of them believe that personalized medicine is currently available only for some subpopulations. They also rated the importance of racial/ethnic background almost as high as the importance of genetic information in the delivery of personalized medicine. Actual elements of personalized medicine rated highest include family history, drug-drug interaction alerts in medical records, and biomarker measurements to guide therapy. Costs of gene-based therapies and genetic testing were rated the most significant barriers. The ratings of several elements and barriers were associated with perceived availability of personalized medicine across subpopulations.

CONCLUSION

While physicians hold differing views about the availability and implementation of personalized medicine, they likewise establish complex relationships between race/ethnicity and personalized medicine that may carry serious implications for its clinical success.

Jumping on the Train of Personalized Medicine: A Primer for Non- Geneticist Clinicians: Part 3. Clinical Applications in the Personalized Medicine Area

The rapid decline of sequencing costs brings hope that personal genome sequencing will become a common feature of medical practice. This series of three reviews aim to help non-geneticist clinicians to jump into the fast-moving field of personalized genetic medicine. In the first two articles, we covered the fundamental concepts of molecular genetics and the methodologies used in genetic epidemiology. In this third article, we discuss the evolution of personalized medicine and illustrate the most recent success in the fields of Mendelian and complex human diseases. We also address the challenges that currently limit the use of personalized medicine to its full potential.

Genomic testing to determine drug response: measuring preferences of the public and patients using Discrete Choice Experiment (DCE)

Background

The extent to which a genomic test will be used in practice is affected by factors such as ability of the test to correctly predict response to treatment (i.e. sensitivity and specificity of the test), invasiveness of the testing procedure, test cost, and the probability and severity of side effects associated with treatment.

Methods

Using discrete choice experimentation (DCE), we elicited preferences of the public (Sample 1, N = 533 and Sample 2, N = 525) and cancer patients (Sample 3, N = 38) for different attributes of a hypothetical genomic test for guiding cancer treatment. Samples 1 and 3 considered the test/treatment in the context of an aggressive curable cancer (scenario A) while the scenario for sample 2 was based on a non-aggressive incurable cancer (scenario B).

Results

In aggressive curable cancer (scenario A), everything else being equal, the odds ratio (OR) of choosing a test with 95% sensitivity was 1.41 (versus a test with 50% sensitivity) and willingness to pay (WTP) was $1331, on average, for this amount of improvement in test sensitivity. In this scenario, the OR of choosing a test with 95% specificity was 1.24 times that of a test with 50% specificity (WTP = $827). In non-aggressive incurable cancer (scenario B), the OR of choosing a test with 95% sensitivity was 1.65 (WTP = $1344), and the OR of choosing a test with 95% specificity was 1.50 (WTP = $1080). Reducing severity of treatment side effects from severe to mild was associated with large ORs in both scenarios (OR = 2.10 and 2.24 in scenario A and B, respectively). In contrast, patients had a very large preference for 95% sensitivity of the test (OR = 5.23).

Conclusion

The type and prognosis of cancer affected preferences for genomically-guided treatment. In aggressive curable cancer, individuals emphasized more on the sensitivity rather than the specificity of the test. In contrast, for a non-aggressive incurable cancer, individuals put similar emphasis on sensitivity and specificity of the test. While the public expressed strong preference toward lowering severity of side effects, improving sensitivity of the test had by far the largest influence on patients’ decision to use genomic testing.