Personalized Medicine and the Practice of Medicine in the 21st Century

The renowned Canadian physician and McGill alumnus got it right. Much of medical science over the past century has documented intra-and inter-individual variability, however the rationale for this variability is not well understood and not often applied in clinical practice. Indeed most therapeutic strategies rely on data derived from randomized clinical trials (RCTs) and large observational studies, and applied to the so-called "statistically average" patient. Although medicine will continue to remain very much an art, just over a hundred years after Osler's observation, we are beginning to understand the factors driving interindividual variability. Armed with details of individual variation, physicians could divide patients into subgroups and predict which are likely to have an aggressive or indolent form of a disease and which would respond to one drug rather than another. The emergence and continued growth of personalized medicine will catalyze fundamental changes at many different levels in the future of health care and health systems. The objective of this special focus article is to describe the role and increasing importance of personalized medicine in health care, as well as discuss some of the ongoing challenges for integrating personalized medicine into contemporary medicine.