Colorectal cancer screening guidelines: how to explain the differences?

Introduction
The advent of new techniques for colorectal cancer (CRC) screening, coupled with the still high incidence and mortality of this disease, has aroused considerable interest in optimizing prevention strategies. In particular, the approval of the immunochemical fecal occult blood test (FOBT) by Medicare in the USA, the progressive improvement in the accuracy of CT colonography, and the further validation of colonoscopy in populations of average risk have expanded the choices for screening.