title: Reduced incidence and mortality from colorectal cancer with flexible-sigmoidoscopy screening: a meta-analysis.
abstract: OBJECTIVE
  To conduct a systematic review and meta-analysis of published population-based randomized controlled trials (RCTs).
  
  
  METHODS
  RCTs evaluating the difference in mortality and incidence of colorectal cancer (CRC) between a screening flexible sigmoidoscopy (FS) group and control group (not assigned to screening FS) with a minimum 5 years median follow-up were identified by a search of MEDLINE and EMBASE databases and the Cochrane Central Register for Controlled Trials through August 2013. Random effects model was used for meta-analysis.
  
  
  RESULTS
  Four RCTs with a total of 165659 patients in the FS group and 249707 patients in the control group were included in meta-analysis. Intention-to-treat analysis showed that there was a 22% risk reduction in total incidence of CRC (RR = 0.78, 95%CI: 0.74-0.83), 31% in distal CRC incidence (RR = 0.69, 95%CI: 0.63-0.75), and 9% in proximal CRC incidence (RR = 0.91, 95%CI: 0.83-0.99). Those who underwent screening FS were 18% less likely to be diagnosed with advanced CRC (OR = 0.82, 95%CI: 0.71-0.94). There was a 28% risk reduction in overall CRC mortality (RR = 0.72, 95%CI: 0.65-0.80) and 43% in distal CRC mortality (RR = 0.57, 95%CI: 0.45-0.72).
  
  
  CONCLUSIONS
  This meta-analysis suggests that screening FS can reduce the incidence of proximal and distal CRC and mortality from distal CRC along with reduction in diagnosis of advanced CRC.
authors.affiliation: Jennifer Shroff, Nirav Thosani, Sachin Batra, Sushovan Guha, Division of Gastroenterology, Hepatology and Nutrition, The University of Texas Medical School at Houston, 77030 TX, United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Shroff
authors.affiliation: Jennifer Shroff, Nirav Thosani, Sachin Batra, Sushovan Guha, Division of Gastroenterology, Hepatology and Nutrition, The University of Texas Medical School at Houston, 77030 TX, United States.
authors.forename: Nirav
authors.initials: N
authors.lastname: Thosani
authors.affiliation: Jennifer Shroff, Nirav Thosani, Sachin Batra, Sushovan Guha, Division of Gastroenterology, Hepatology and Nutrition, The University of Texas Medical School at Houston, 77030 TX, United States.
authors.forename: Sachin
authors.initials: S
authors.lastname: Batra
authors.affiliation: Jennifer Shroff, Nirav Thosani, Sachin Batra, Sushovan Guha, Division of Gastroenterology, Hepatology and Nutrition, The University of Texas Medical School at Houston, 77030 TX, United States.
authors.forename: Harminder
authors.initials: H
authors.lastname: Singh
authors.affiliation: Jennifer Shroff, Nirav Thosani, Sachin Batra, Sushovan Guha, Division of Gastroenterology, Hepatology and Nutrition, The University of Texas Medical School at Houston, 77030 TX, United States.
authors.forename: Sushovan
authors.initials: S
authors.lastname: Guha
mesh_terms: D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology* / Q000517:prevention & control; D055088:Early Detection of Cancer / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D015994:Incidence; D016017:Odds Ratio; D011237:Predictive Value of Tests; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D020694:Sigmoidoscopes; D012812:Sigmoidoscopy / Q000295:instrumentation / Q000379:methods*
keywords: Colorectal Cancer; Flexible sigmoidoscopy; Incidence; Meta-analysis; Mortality; Randomized control trials