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Is there a place for precision medicine in public health?

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By: Megan Roberts, Ph.D.

photo credit: BWJones via photopin cc

In January 2014, President Obama announced the Precision Medicine Initiative (PMI), the goal of which is to transform treatment and prevention from a “one size fits all” approach into an increasingly tailored approach that accounts for an individual’s genes, environment and lifestyle. While bipartisan support and PMI leadership have propelled the initiative forward, some public health researchers have voiced skepticism over whether precision medicine will improve public health. Some have even called precision medicine “a distraction from the goal of producing a healthier population.” These arguments often point to the need for public health researchers to address social determinants of health to improve overall public health, and reduce health disparities in a country that spends more on health care, but endures worse health outcomes compared to other developed countries. Furthermore, by definition, public health refers to the prevention of disease and the promotion of health among populations as a whole, which seems antithetical to the “precision medicine” paradigm, with its focus on individual-level nuances. By focusing on individual health, there is a fear that we will we lose sight of public health’s goal to improve the health of our whole population, particularly underserved groups. This begs the question: is there a place for precision medicine in public health?

 While aspects of the PMI are transformative (e.g., the MATCH trial and the PMI cohort), precision medicine principles are foundational for current prevention and treatment practices. While we might immediately think “genetics” when we hear “precision medicine,” the precision medicine approach is actually much broader than only focusing on genetics, by also incorporating an individual’s environment and lifestyle for both disease prevention and treatment. Since the early 1990s, a large body of evidence has demonstrated that the effects of public health interventions are often moderated by individual level characteristics, including biological, environmental and lifestyle factors. Often, tailored approaches addressing these moderators are more effective than non-tailored approaches. As such, to move public health research forward, we must consider the interactions between individual level factors and public health strategies. This paradigm reflects the same thinking behind precision medicine, and aligns with conceptual frameworks that drive public health research and practice.

Precision medicine is already incorporated into current disease prevention strategies. Increasingly, cancer-screening programs tailor prevention strategies through targeted, risk-based screening. In a health care system with finite public health resources, targeting cancer prevention efforts to those who will receive the greatest benefit is critical. For example, breast MRI is a highly sensitive breast cancer-screening tool; however, the test has high rates of false positive results. As such, the benefits of breast MRI only outweigh the harms for women who are at high risk for breast cancer.  In order to identify women who are at high risk, researchers have developed risk-based models that incorporate individual level risk factors, as well as genetic tests to identify genetic mutations that confer an increased cancer risk.  For those at significantly higher risk of breast cancer, clinical guidelines recommend MRI screening, as breast MRI is cost-effective and improves health outcomes in this setting.  A risk-based approach is also used in lung and cervical cancer screening. Specifically, lung cancer screening tailors on factors including smoking history, and HPV vaccination tailors on high-risk populations, including men who have sex with men and those with HIV. Precision medicine approaches for screening demonstrate an important application of precision medicine in public health, and have led to effective prevention strategies for high-risk groups.

In addition to prevention, linking individuals to high quality care remains a tenet of public health. Improved understanding of the genetic basis for disease has improved treatment strategies, particularly in cancer care. Today, high quality cancer care relies on targeting treatment using genetic tumor markers. Breast cancer, once viewed as a single disease, is now known to be multiple subtypes of breast cancer that can be distinguished by tumor genetics. Conversely, other studies have uncovered similarities between tumors that originate in different organ sites. For example, one study has found that lung squamous cell carcinoma, head and neck, and a subset of bladder cancers cluster by gene expression patterns, meaning these cancers all have genetic similarities. As such, therapeutics that target specific tumor markers have been developed.  There are drugs on the market that target tumor markers that occur in multiple tumor sites, such that a lung cancer patient may receive the same drug as a pancreatic cancer patient who has a similar genetic mutation. This treatment demonstrates a shift toward considering cancer according to a tumor’s genetics rather than by a tumor’s organ site.  Precision medicine programs have emerged that use this cancer treatment approach , and the MATCH trial—a component of the PMI—will elucidate the effectiveness of this approach. Similar precision medicine approaches could potentially be extended to other disease areas in the future.

Overall, the use of individualized information in research, prevention and treatment is neither new nor incongruous with the goals of public health.  “Precision” public health researchers  must ensure that precision medicine is equally accessible to all patients, with a strong focus on dissemination and implementation research around precision medicine approaches. While the PMI and public health priorities may not always mirror one another, to pit public health against precision medicine is a mistake.  Public health and precision medicine can synergize towards common goals of disease prevention and control. Precision medicine has helped researchers and clinicians identify important interactions between individual-level factors and life-saving prevention and treatment strategies. Research findings through the PMI will only further this progress and improve population health.

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Written by sciencepolicyforall

April 7, 2016 at 12:00 pm

Posted in Essays

Tagged with ,

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