The Northern-European Initiative on Colorectal Cancer

Colorectal cancer (CRC) is a major burden in western countries. The disease develops from
precursor lesions during a long time-interval. Colonoscopy can detect and remove CRC
precursor lesions and may thus be effective for CRC prevention. Many national and
international health organisations demand evidence from randomised trials to reduce
incidence or mortality of the target disease before advocating population-wide cancer
screening. However, while colonoscopy screening for the prevention of colorectal cancer is
established in the United States and several European countries, no randomised trials exist
to quantify the possible benefit of colonoscopy screening. NordICC is a randomised trial
investigating the effect of colonoscopy on CRC incidence and mortality.

NordICC is a multicentre, randomised trial in Nordic countries, the Netherlands and Poland.
A minimum of 66 000 individuals, age 55-64 years, are drawn randomly from the population
registries in the participating countries. 22 000 are invited for once-only colonoscopy (2:1
randomisation). Expected work-load with 50% compliance will be 11,000 colonoscopies. At the
screening examination, all detected lesions are biopsied and removed whenever possible. The
remaining 44 000 individuals (control group) are not offered any screening examination (care
as usual).The primary study aims are CRC incidence and CRC mortality after 15 years of
follow-up, with an interim analysis after 10 years of follow-up. In an intention-to-treat
approach, a risk reduction of CRC mortality of 25% in the colonoscopy screening group
compared to the control group is expected after 10 years follow-up, estimating 50%
compliance in the screening group.