The Shift From Personalized Medicine to Precision Medicine and Precision Public Health: Words Matter!

Advances in genomics and other ‘omic’ technologies have ushered in a new era variably called “personalized” or “precision” medicine, which takes into account individual genetic and other sources of variability in disease treatment and prevention.

In the past decade, we have seen a significant growth in interest and usage of the terms personalized and precision medicine.  The terms precision, personalized, and individualized medicine have often been used interchangeably by many authors (including myself). The term P4 medicine has also been proposed (predictive, preventive, personalized and participatory medicine). By and large, the terms personalized medicine and precision medicine have had most currency. Recently, however, there has been a prominent shift from “personalized medicine” towards “precision medicine”. This Google trends analysis shows an accelerated search for “precision medicine” in the past two years, perhaps propelled by the 2015 United States Precision Medicine Initiative (see figure below). Similarly, a PubMed query shows that in 2005, there was only one paper mentioning “precision medicine”, compared to 74 papers mentioning “personalized medicine”. In 2015, there were 1737 papers with “precision medicine” compared to 1529 papers mentioning “personalized medicine”.

Does this change in words represent just semantics or is it an important conceptual shift in the scientific understanding of health and disease and its application to treatment and prevention? As evidenced by the searches above, many still use both terms, and one frequently encountered point of view is that “there’s not one iota of difference between the definitions of personalized and precision medicine.“

A strong rationale for the shift towards precision medicine was laid out in a 2011 report from the National Research Council (NRC). The report explored the need for “a new taxonomy of human disease based on molecular biology” and to develop a potential framework for creating one. As a result of the explosion of genomic and other molecular information on humans and other species, the report discusses the need to use “large, as-yet-untapped opportunities to use these data to improve health outcomes.”  The report envisioned a comprehensive disease classification that combines information from biomedical-research, public health, and health-care-delivery communities towards advancing knowledge of disease pathogenesis and improving health. The report expressed concern that the use of the term “personalized medicine” could imply that treatments and preventions are being developed uniquely for each individual. After all, isn’t medicine supposed to be personalized to begin with? On the other hand, the focus of “precision medicine” is to explore how treatment or prevention approaches can be developed based on the combination of genetic, environmental, and social factors which could be targeted to individuals or populations.

To be sure, precision medicine and personalized medicine are highly related and genomics plays a big role in both. However, even highly personalized information may or may not lead to improved health outcomes. Moreover, precision medicine approaches may lead to non-personalized interventions that can be used population-wide.

A prominent example of a highly personalized test is direct-to-consumer (DTC) genetic testing that has been proposed to improve health and prevent common diseases. In many ways, DTC genetic tests are the opposite of precision medicine. In spite of their deceptive appeal, they “deliver uncertain information and create patient expectations that may align poorly with evidence; clinical priorities; or, in some cases, the patient’s best interests.”

On the other hand, a precision approach to disease could lead to new insights into disease biology and occurrence whose applications may be population wide. For example, molecular studies in familial hypercholesterolemia (FH), a genetic disorder with high cholesterol and premature atherosclerotic heart disease, have led to the development of cholesterol lowering drugs such as statins and more recently PCSK9 inhibitors. These drugs could be used to lower cholesterol levels in the population and not only among FH patients.

One could even extend the concept of “precision medicine” envisioned in the 2011 NRC report to “precision public health” which is not just about “genes, drugs and diseases.” As we gain more insights into complex life course interactions between biological factors with a range of personal, environmental and social determinants of health, can we use this knowledge to measure and track occurrence of disease in communities and to implement effective interventions that can benefit all segments of the population? A prominent example of precision public health is the use of pathogen genome sequencing technologies in tracking infectious disease outbreak sources, spread and susceptibility to antibiotics. CDC’s Advanced Molecular Detection Initiative is already combining these technologies with bioinformatics and epidemiology to enhance public health surveillance, investigations and control of infectious diseases.

Dr. Sue Desmond-Hellmann, Chief Executive Officer of the Gates Foundation, who was a co-chair of the 2011 NRC report, has also begun laying out a vision for precision public health. In a recent interview, she talked about bringing her passion for precision medicine to public health. “As a cancer doctor, I was part of this new targeted therapy, getting the right medicine to the right patient. So today, I’m interested in something I’d call precision public health. Can we bring that same innovation, that speed, that ability to use big data to the problems we’re trying to solve? That is not a one-cause passion. That is my wish: To bring all of this intellectual data, understanding and tracking of diseases to bear for things that affect the poor every bit as much as we have traditionally done for the rich.” She also elaborated on the concept of precision public health in an Aspen Institute Public Health Grand Rounds.

In closing, a simple shift from “personalized medicine” to “precision medicine” allows us to imagine a future practice of medicine and public health in which large-scale biologic, personal, environmental and social information can be analyzed with new computational tools to identify determinants of health and disease, and to develop both individualized and population-level interventions to treat and prevent human disease and improve health equity.