Colorectal cancer screening

Abstract

Colorectal cancer (CRC) is one of the most common cancers in the Western world, with an estimated incidence of 148 810 cases in the USA in 2008, and about 50 000 deaths from this disease. If detected early, patients with disease localised to the colonic wall have a 5-year survival of 90%. The 5-year survival for patients with regional disease is 68%, and a dismal 10% in the presence of distant metastases. Given that most sporadic CRCs develop
from adenomatous polyps, it has been shown that CRC risk can be reduced by removal of the precursor lesion, the adenomatous polyp. However, not all polyps will develop into cancers; the polyp size and histology are determining factors for CRC risk.1 Advanced adenomas are defined as being 10 mm or greater in size, have a villous component, or show features of high-grade dysplasia.