Genetic Panel Testing: Points of View
An interview with Steven Ralston
Steven Ralston |
The goals of expanded gene panel testing seem beneficent – to enable better diagnosis and treatment of complex diseases with the ultimate aim of improving health. In reality, though, there remains a disjuncture between these hopeful goals and what we can achieve in practice. Our sequencing capacity continues to outpace our ability to interpret the volume of genomic data we generate. Similarly, our diagnostic capability continues to exceed the availability of treatments. One consequence is that panels may generate results with unclear significance, limited to no clinical utility, or no relation to the original purpose of testing. Variants of uncertain significance (VUS), or those associated with low- to moderate-susceptibility genes, can leave patients confused or with information on which they cannot act. Why, one might ask, does the scope and scale of gene panels continue to grow despite a limited ability to interpret them?
In the United States, commercialization and drives to increase market share are one contributing factor. The implicit ethos seems to be that the inclusion of more in a panel increases its value and market appeal – a “bigger is better” mentality. In a competitive commercial environment where companies market directly to clinicians and patients, more comprehensive gene panels may be an attempt to increase sales, rather than to improve clinical or patient utility. That’s not to say that there are no benefits to panel testing, or that commercialization is the sole driver of their expansion. My aim is to remind readers that commercialization is an important factor in the increasing use and availability of panel testing in the United States – and that it may, at times, override clinical consensus and the evidence base.
There are ethical consequences related to patient beneficence and the duty to do no harm, as well as to the appropriate and just allocation of limited clinical resources. Results like VUS can cause confusion, misunderstanding and anxiety for patients – and may even result in harm through unnecessary treatment. But it is equally important to acknowledge that excessive testing can also create burdens for clinical staff and drain precious resources, for instance when large panels require additional time for interpretation and to communicate results to patients in a meaningful way. As more variants are added to panels – especially those with low risk or unclear clinical significance – there will be a parallel rise in strain on already limited resources.
Gene panels have the potential to improve clinical care – and, in some situations, they already do. At the same time, it is important not to lose sight of the complex on-the-ground difficulties they may create for patients and clinicians alike, nor of factors like commercialization that contribute to their increasing availability and uptake. This should act as a reminder: when it comes to gene panels, more is not always better.
Jessica Mozersky is an Assistant Professor of Medicine at Washington University School of Medicine in St. Louis, USA. Her research explores the ethical and social implications of new biomedical and genomic technologies including cancer genetic testing, prenatal genetic screening, whole genome sequencing, and PET neuroimaging.