Changes in colorectal cancer screening use after introduction of alternative screening offer in Germany: Prospective cohort study

In October 2002, screening colonoscopy was added to the German colorectal cancer (CRC) screening program as an alternative to fecal occult blood test (FOBT). We aimed to evaluate the change in CRC screening use after introduction of the dual screening offer and to assess determinants of screening use. Data were drawn from a population-based cohort study initiated during 2000-2002 in Germany (n = 5,845, age range at recruitment: 50-75 years). We conducted both cross-sectional and longitudinal analyses to obtain uptake rates of CRC screening based on four waves of data. Age-group specific proportions of participants having had FOBT within 2 years remained essentially unchanged at 61-67% between 2000 and 2002 (1st wave) and 2005-2007 (3rd wave). The proportions of participants having undergone screening colonoscopy within 10 years increased from 23-29% to 46-57%, leading to a substantial overall increase in being up-to-date with CRC screening from 66-68% to 77-80%. In 2008-2010 (4th wave), FOBT use declined and colonoscopy use continued to increase. Obesity was significantly associated with lower prevalence of being up-to-date with FOBT (odds ratio [OR] at 8-year follow-up 0.68; 95% confidence interval [CI], 0.58-0.80) and screening colonoscopy (OR, 0.73; 95% CI, 0.62-0.86). Also, smokers were less likely to have ever used FOBT (OR, 0.54; 95% CI, 0.40-0.75) or colonoscopy (OR, 0.75; 95% CI, 0.63-0.90) compared to nonsmokers. After the introduction of dual screening offer, the overall adherence to CRC screening steeply increased, mainly due to an increase in screening colonoscopy uptake. Screening tests kept being underused by obese people and smokers who are at elevated CRC risk.