[Sometimes less is more. Preventing overdiagnosis by sharing decisions].

In this article, we will define «quaternary prevention», which consists in minimizing the iatrogenic effects of medical interventions, and more specifically the notion of «overdiagnosis». We will then discuss how a poor appreciation of the risks, on the part of both patients and clinicians, seems to fuel the phenomenon. We will discuss the interest of placing quaternary prevention within the broader framework of Shared Decision Making. We will focus on one of the stages of Shared Decision Making process, that of risk communication. Finally, we'll conclude that, fundamentally, clinicians should not only share information with patients, but also the power to decide.