Early colorectal cancer detection—Current and evolving challenges in evidence, guidelines, policy, and practices

The understanding at the beginning of the last century that colorectal cancer began as a localized disease that progressed and became systemic, and that most colorectal cancer arose from adenomatous polyps gave rise to aggressive attempts at curative treatment and eventually attempts to detect advanced lesions before they progressed to invasive disease. In the last four decades, steadily greater uptake of screening has led to reductions in colorectal cancer incidence and mortality. However, the fullest potential of screening is not being met due to the lack of organized screening, where a systems approach could lead to higher rates of screening of average and high risk groups, higher quality screening, and prompt followup of adults with positive screening tests. ABSTRACT: Since the beginning of the 20th century, there has been a general understanding that colorectal cancer is a clonal disease that progresses from a localized stage with a favorable prognosis through progressively more advanced stages which have progressively worse prognosis. That understanding led first to determined efforts to detect and treat early stage symptomatic disease, and then to detect pre-symptomatic colorectal cancer and precursor lesions, where there was hope that the natural history of the disease could be arrested and the incidence and premature mortality of colorectal cancer averted. Toward the end of the last century, guidelines for colorectal cancer screening, growth in the number of technical options for screening, and a steady increase in the proportion of the adult population who attended screening contributed to the beginning of a significant decline in colorectal cancer incidence and mortality. Despite this progress, colorectal cancer remains the third leading cause of death among men and women in the United States. Screening for early detection of precursor lesions and localized cancer offers the single most productive opportunity to further reduce the burden of disease, and yet nearly four in five deaths from colorectal cancer are associated with having never been screened, not recently screened, or not followed up for an abnormal screening test. This simple observation is a call to action in all communities to apply existing knowledge to fulfill the potential to prevent avertable incidence and mortality.