New horizons in nonpolypoid colorectal carcinogenesis

Tracing and removing colon polyps during internal examination can stop the development of colorectal cancer at an early stage. Therefore, in the Netherlands from 2013 on the population older than 55 years will be screened. Recent research, however, shows that the preventive effect of colon examination is considerably less in the right part of the colon. A possible explanation is the contribution of so-called flat colon polyps. This type of colon polyps is more difficult to identify and remove and possible also of a more aggressive nature. This dissertation about the clinical and molecular characteristics of flat colon polyps shows that they make a larger contribution to the development of colorectal cancer in the right than in the left part of the colon. Adequate tracing of flat colon polyps therefore appears a condition for effective population screening for colorectal cancer.