When Science Fails: The Promise and Limits of Precision Medicine

For centuries, humans have used science to explain their world. From the principles that suspend the planets in orbit to the relational pull of predator and prey, we turn to science to both examine and rationalize the experience of life. But does our reliance on science have a limit, particularly in medicine, where the “why” of disease can often escape scientific explanation?

For example, historically, medicine has poorly understood why one person gets sick and another doesn’t, particularly for complicated illnesses like cancer, diabetes, or heart disease, where multiple factors contribute to risk. Similarly, it’s been difficult to pinpoint why one medication works well for one person but not another.

And in the case of social determinants of health, medicine has yet to chart the physiology of disadvantage. That means, while we know poor people tend to be sicker, we don’t fully understand how poverty and discrimination manifest physiologically to produce disease; although there are exciting theories about stress hormones and organ function.

And so the why has evaded us, until now.

In January 2015, President Obama invested $215 million in a national Precision Medicine Initiative to use what science knows about the human genome to personalize the way doctors diagnose and treat disease.

The idea is that by using a wide range of biomedical information — including molecular, genomic, cellular, clinical, behavioral, physiological, and environmental parameters, physicians and scientists will have new tools to understand disease and determine the treatments that work best for each individual’s illness and DNA.

With such a sizable investment from the Obama administration and the partnership of trusted institutions in the scientific community including the National Institutes of Health (NIH), National Cancer Institute, and the Food and Drug Administration, this Precision Medicine Initiative promises to improve the diagnostic strength and treatment success of modern medicine. The significance of that promise cannot be underestimated.

But as we turn to science to answer the elusive why, we have to be mindful of where science has failed in the past. This is to set reasonable expectations but also to avoid repeating past mistakes. So as we move forward, here are 2 things to keep in mind.

First, as we narrow our focus from the population to the individual, it may be easy to overlook the way certain diseases are disproportionately prevalent in certain communities. If we then, limit our evaluation to the individual, their DNA, and their illness, we may miss the aggregate data that compels us to also investigate disease at the community level, where local resources and public policy may profoundly shape disease patterns and prevalence. Which is to say, while some disease is best explained from the lens of a microscope, other disease is best appreciated with a panoramic view of the environmental conditions in which that disease persists.

Second, to capture enough data to understand the human genome, the NIH and its collaborators are aiming to enroll 1 million American volunteers in the Precision Medicine research cohort. But a study published in 2014 found that non-whites account for less than 5% of clinical trial participants. More specifically, of the 10,000 clinical trials reviewed in that data, only 150, or less than 2%, focused on a racial or ethnic minority population.

So, if the Precision Medicine cohort is anything like the clinical trial cohorts from the past, women, minorities, and the elderly may be underrepresented; not to mention undocumented “non-Americans” who are generally excluded from scientific research. That means, while some patients will receive care uniquely tailored to them, women, minorities, the elderly, and the undocumented, may get care that was studied, tested, and developed, mostly for young white men. So as we endeavor to improve our understanding of human biology and disease, we have to make demonstrated efforts to enroll those science has historically forgotten.

Probing the human genome for the answers to medicine’s greatest questions will almost certainly lead to innovations and improvements in the health of our population. But as with most innovations, without careful and thoughtful execution, the impact may be limited. In Precision Medicine, we risk continued exclusion of certain populations from the benefits of science. This is when science fails, when it is unable to capture the breadth and meaning of the human experience. So if Precision Medicine does not couple its inquiry into DNA and disease with an equally rigorous examination of the biologic imprint of social stress, poverty, and discrimination, we may be no why-ser, than when we started.


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