Original ResearchFull Report: Clinical—Alimentary TractReduced Risk of Colorectal Cancer Up to 10 Years After Screening, Surveillance, or Diagnostic Colonoscopy
Section snippets
Study Design and Study Population
Our analysis is based on data from the DACHS (Darmkrebs: Chancen der Verhütung durch Screening) study, a population-based case-control study conducted in the Rhine-Neckar area of Germany since 2003. In Germany, guaiac-based FOBT (samples from 3 consecutive days) and colonoscopy have been offered for primary screening in an opportunistic manner for a number of years. Between 1977 and 2002, annual screening by FOBT was offered for people aged 45 years or older. Since October 2002, annual
Results
The main characteristics of the cases and controls are shown in Table 1. Fifty-nine percent of the cases and controls were men, and the median age was 70 years in both groups. A family history of CRC and smoking were more common among cases than among controls, whereas controls more often had a higher level of education and had ever used aspirin, NSAIDs, or HRT regularly. The majority of cases were diagnosed in stage II or III, but all 4 stages were represented with several hundreds of cases.
Discussion
In this large population-based study, the risk of CRC was small up to 10 years after screening colonoscopy. Compared with people who never underwent colonoscopy, the risk of CRC was reduced by approximately 90% after controlling for confounding factors, and the risk was still reduced by almost 80% even for cancer in the right colon. A somewhat lower but still substantial risk reduction (by 67%–85% for total CRC and by 29%–78% for cancer in the right colon) was observed for those who underwent
Acknowledgments
The authors thank the study participants and the interviewers who collected the data, the hospitals and cooperating institutions that recruited patients for this study (Chirurgische Universitätsklinik Heidelberg, Klinik am Gesundbrunnen Heilbronn, Sankt Vincentiuskrankenhaus Speyer, Sankt Josefskrankenhaus Heidelberg, Chirurgische Universitätsklinik Mannheim, Diakonissenkrankenhaus Speyer, Krankenhaus Salem Heidelberg, Kreiskrankenhaus Schwetzingen, Sankt Marien und Sankt Annastiftkrankenhaus
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Conflicts of interest The authors disclose no conflicts.
Funding Supported by grants from the German Research Council (Deutsche Forschungsgemeinschaft, grants BR 1704/6-1, BR 1704/6-3, BR 1704/6-4, and CH 117/1-1) and the German Federal Ministry of Education and Research (grants 01KH0404 and 01ER0814). The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.