Doctors have long recognized that outcomes from treating the same disease can vary widely from patient to patient when using the same or similar treatment strategies. Would it not be wonderful if we could identify the factors that cause those differences and craft a specific treatment that would work for each individual?
Enter precision medicine, which is now at the center of achieving that goal. Precision medicine is generally defined as the use of a specific treatment based on the unique traits of each person. But how realistic is this? Is it really possible to detect such differences and develop treatments that target these traits, altering the course of a particular disease in a particular person?
To begin, there are a few misconceptions about the meaning of precision medicine. First, the process of precision medicine does not mean the creation of a treatment, drug, or medical device unique to every patient; although an alluring ideal, it is currently impossible. Instead, precision medicine attempts to find similar gene variations in small subgroups of patients to which a particular treatment can then be applied effectively; this approach is not only possible but also much more likely to be successful. Second, although precision medicine is based on variations in our genes, whether those genes actually become expressed is determined by genes as well as environmental and lifestyle factors via epigenetics. Precision medicine must also encompass each person’s epigenetic factors to have a benefit.
In actuality, we have already seen the possible benefits of precision medicine, specifically in the study of cancer. For example, we have discovered that certain cancers are driven by specific mutations in tumor genes; so treatments are being developed that may be successful at interfering with those mechanisms. However, although some targeted therapies based on genetics have been successful against specific cancer subtypes, many other predicted treatments based on mutations identified in tumors do not seem to be very effective or long lasting. For example, a targeted drug used in melanoma patients with a BRAF mutation may only work for about 7 months. There are also labs that test for hundreds of mutations, but often the detected mutations are not the ones driving the tumor and therefore the associated treatment to block that mutation may be ineffective.
Currently, there are about 2,000 diseases for which genetic testing exists. However, the ability to correlate that information with epigenetic factors and apply it to treatment strategies is only in its infancy. The future emphasis of precision medicine will be on diseases such as Alzheimer’s, obesity, heart disease, diabetes and various mental illnesses. All of these diseases are very complex, with multiple genes and intertwining epigenetic factors determining a patient’s eventual outcome. Therefore, each of these diseases may need to be addressed using different approaches, many of which have not yet been developed.
Precision medicine will be an enormous undertaking; it will require significant amounts of money, research, and extensive collaboration among all medical providers. But it could change how medicine is practiced and taught, how health care is provided to each patient, and how medical providers are reimbursed for their services. There will also be safety and privacy concerns; data will be collected on millions of people, which could be targeted by hackers for any number of purposes. Such a breach could deprive people and their families of privacy and trigger prejudicial actions from outside sources. We will also need a much more effective electronic health record (EHR) system. At present, EHR data is too fragmented and impractical for the demands of precision medicine. Additionally, new research will need to focus on select groups of patients rather than an overall population, as has been done in the past. And all of this will take time to incorporate–on the order of decades, not years.
Precision medicine holds great potential but faces significant challenges before it can be used effectively. Full implementation will not happen overnight, and there will be many failures on the way. However, as a starting point, it is a worthwhile endeavor so long as we are cautious and understand the impact and implications it will have on our health care system.
About The Author: Larry Altshuler, MD, Southwestern Regional Medical Center, (Tulsa, OK), is the author of DOCTOR, SAY WHAT? The Inside Scoop to Getting the Best Health Care and DOCTOR, SAY WHAT? The Guides: What Works and What Doesn’t for Over 90 Medical Conditions. He is a practicing Internist, Hospitalist and Integrative practitioner at a major cancer center in the Midwest.