Colonoscopy screening markedly reduces the occurrence of colon carcinomas and carcinoma-related death: a closed cohort study.

Background Colonoscopy with a possible polypectomy is an efficient and preferred screening method to reduce the incidence of colorectal cancer (CRC). However, critics argue that, to date, a reduction of incidence and mortality from CRC has not been demonstrated in a population-based setting. Objective To compare the incidence of and mortality from CRC among individuals screened by colonoscopy and non-screened individuals. Design A closed cohort study. Setting Population-based setting in a precisely defined area with a low level of population migration. Patients This study involved 1912 screened and 20,774 control participants. Intervention CRC cases in this closed cohort study were prospectively collected during the screening period of 1 year and the follow-up period of 6 years. Main Outcome Measurements Follow-up data were corrected for negligible migration balance in the area. Tumor characteristics and risk or protective factors, age and sex, participation in general health screening examinations, history of CRC in a first-degree relative, smoking status, body mass index, frequency of sports activity, eating habits, and patients' professions were recorded. Results Overall cancer incidence was significantly lower in the screened group compared with the non-screened group (adjusted odds ratio [OR] 0.31; 95% confidence interval [CI], 0.16-0.59; P P = .04). Risk factors such as lifestyle, smoking, and body mass index as well as family history were similar in both groups. Blue-collar workers had a higher incidence of CRC compared with professionals. The risk factors for CRC were a positive family history and smoking. Limitations Number and ethnicity of the participants, non-randomized study. Conclusion Colonoscopy with polypectomy significantly reduces CRC incidence and cancer-related mortality in the general population.