Colorectal cancer incidence in Germany: stage-shift 6 years after implementation of a colonoscopy screening program. 
In 2002, colonoscopy was introduced as a tool for colorectal cancer screening in Germany.  The long-term objective was to reduce the incidence in colorectal cancer (CRC) by detection and removal of advanced adenomas.  Currently, the effect of colonoscopy screening on the population-based incidence of CRC in Germany is unknown.  We provide data on stage-specific (age-standardized) incidence rates in three federal states in Germany, 6 years after the implementation of colonoscopy.  Between 2002 and 2008 a statistically significant decrease in CRC incidence could be observed (annually 3.0%, 95% confidence interval [CI]: -3.8; -2.2).  The decline could be observed in all advanced tumor categories (T2, T3, and T4), whereas the incidence of in situ carcinomas (Tis) increased annually by 51.6% (95% CI: 28.0; 79.4) until 2004, and remained stable until 2008.  The observed changes cannot be attributed definitively to the screening activities, but the presented data support a possible causal association.