Barriers to Implementation of Precision Medicine for Cancer Treatment in the U.S. Healthcare System.
Cancer is a complex disease caused by a combination of genetic factors and environmental and life style influences. These manifest across a wide spectrum of symptoms, outcomes, and response to
therapy. Precision medicine in oncology implements clinical screening and tissue molecular profiling to characterize the genetic makeup of the patient (i.e., germline DNA) and of the tumor
(i.e., somatic mutations). This consequently enables the identification and validation of treatments to reduce side effects, and improve outcomes. For example, current treatment for a breast cancer patient who has estrogen receptor positive (ER+) breast cancer will potentially include tamoxifen, a drug shown to be effective against early stage receptor-positive cancers. However, tamoxifen is metabolized by the polymorphic CYP2D6 enzyme; certain genetic variants in the CYP2D6 gene may result in reduced drug efficacy in patients carrying those variants 1. Therefore, the knowledge derived from both a patient’s phenotypic and molecular profile has the potential to support clinical decision-making by understanding the likely benefits and risks of a particular