Estimated long-term effects of the initial 6 years of the German screening colonoscopy program

BackgroundColorectal cancer is the most common cancer in Germany. Screening colonoscopies have been offered as a primary screening tool in Germany since the end of 2002.ObjectiveTo estimate the numbers of clinically manifest colorectal cancers prevented by detection and removal of advanced adenomas in the initial 6 years of the program.DesignMarkov model with single-year transitions.SettingGerman screening colonoscopy program.PatientsParticipants in the screening colonoscopy program from 2003 to 2008.InterventionsScreening colonoscopy with the removal of advanced colorectal neoplasms.Main Outcome MeasurementsThe expected numbers of incident colorectal cancers prevented by detection and removal of advanced adenomas.ResultsAn estimated total number of 73,024 cases of colorectal cancer might have developed from the removed advanced adenomas and become clinically manifest between 55 and 84 years of age in the absence of screening colonoscopy. This number exceeds the number of colorectal cancers diagnosed in 2002 by 27%. Among prevented cancers, 8%, 43%, and 49% would have occurred at ages 55 to 64, 65 to 74, and 75 to 84 years (median age 74 years), respectively; 60% and 40% would have occurred among men and women, respectively; and 22%, 32%, 25%, and 20% would have occurred within 1 to 5, 6 to 10, 11 to 15, and 16 to 30 years, respectively, after colonoscopy (median 10 years).LimitationsDiagnoses of advanced adenomas are based on records from a large number of endoscopists and pathology laboratories.ConclusionsDespite relatively low screening participation, the German screening colonoscopy program is expected to make a major contribution to the prevention of colorectal cancer, even though most of the impact will only be seen in the longer run.