Epidemiology, molecular changes, histopathology and diagnosis of colorectal cancer

Background: Colorectal cancer is one of the most common malignant diseases in the industrialized nations. Despite advances in research on tumor development and biology, improved therapeutical concepts, and an increasing motivation to undergo screening examinations and surveillance programs the overall mortality remains high. Methods: PubMed database was used to screen the current literature for the topics of epidemiology, colorectal cancer development, histopathologic features, and diagnosis in colorectal cancer. Results: A general overview of epidemiologic data in terms of incidence, geographic differences in occurrence and risk factors is given. Molecular mechanisms for the formation of colorectal cancer within the adenoma-carcinoma sequence are explained and additional aspects such as ploidy-status of colorectal tumors and microsatellite instability put into perspective. Various variables of routine histopathologic evaluation are summarized, more advanced analyses explained and prognostically relevant features listed. Diagnostic workup and staging of patients with colorectal cancer are based on several different techniques which are discussed for their effectivity, sensibility and sensitivity. Conclusions: Early detection of colorectal cancer together with a more detailed understanding of tumor heterogeneity and the prospect of tailoring individualized therapeutical concepts constitute essential factors in order to further ameliorate the outcome of colorectal cancer patients.