Effect of screening with flexible sigmoidoscopy on colorectal cancer incidence and mortality

Colorectal cancer (CRC) is a leading cause of cancer death in the Western world. Norway is one of the countries in the world with the highest incidence of CRC. The reason for this is unknown. The Norwegian Colorectal Cancer Prevention trial (NORCCAP) is a randomised controlled trial performed in 1999-2001. 100,210 people aged 50-64 years living in Telemark County and Oslo city was identified through the population registry and randomly assigned to a screening group or control group. The screening group w as offered a once only screening examination by means of flexible sigmoidoscopy (endoscopic examination of the rectum and lower half of the colon). The aim of the screening examination was to detect early, asymptomatic CRC with a favorable prognosis and t o remove lesions (adenomas) with a potential for later development into CRC. The control group were not offered any intervention and continued to receive health care as usual. The primary aim of the project is to compare mortality and incidence of CRC in the screening group and control group ten years after screening. The secondary objective will be to investigate the impact of findings at the screening examination to the risk of later development of CRC. The stay at Harvard will be focused on analyzing these data in cooperation with professors in statistics and epidemiology. A major aim of this study is to provide data for political decisions on CRC screening in Norway, data which will not be made available by other projects than the NORCCAP trial. Thus , the project is expected to strongly influence political decisions. The most critical R&D challenge will be the completeness of data from Norwegian public registries before the project period starts in August 2013, but will likely be available during aut umn 2012.