Effect of Flexible Sigmoidoscopy-Based Screening on Incidence and Mortality of Colorectal Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

B. Joseph Elmunzer, Rodney A. Hayward, Philip S. Schoenfeld, Sameer D. Saini, Amar R Deshpande, Akbar K. Waljee

Research output: Contribution to journalArticle

131 Citations (Scopus)

Abstract

Background: Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs. Methods and Findings: Medline and Embase databases were searched for eligible articles published between 1966 and 28 May 2012. After screening 3,319 citations and 29 potentially relevant articles, two reviewers identified five RCTs evaluating the effect of FS screening on the incidence and mortality of CRC. The reviewers independently extracted relevant data; discrepancies were resolved by consensus. The quality of included studies was assessed using criteria set out by the Evidence-Based Gastroenterology Steering Group. Random effects meta-analysis was performed. The five RCTs meeting eligibility criteria were determined to be of high methodologic quality and enrolled 416,159 total subjects. Four European studies compared FS to no screening and one study from the United States compared FS to usual care. By intention to treat analysis, FS-based screening was associated with an 18% relative risk reduction in the incidence of CRC (0.82, 95% CI 0.73-0.91, p<0.001, number needed to screen [NNS] to prevent one case of CRC = 361), a 33% reduction in the incidence of left-sided CRC (RR 0.67, 95% CI 0.59-0.76, p<0.001, NNS = 332), and a 28% reduction in the mortality of CRC (relative risk [RR] 0.72, 95% CI 0.65-0.80, p<0.001, NNS = 850). The efficacy estimate, the amount of benefit for those who actually adhered to the recommended treatment, suggested that FS screening reduced CRC incidence by 32% (p<0.001), and CRC-related mortality by 50% (p<0.001). Limitations of this meta-analysis include heterogeneity in the design of the included trials, absence of studies from Africa, Asia, or South America, and lack of studies comparing FS with colonoscopy or stool-based testing. Conclusions: This meta-analysis of randomized controlled trials demonstrates that FS-based screening significantly reduces the incidence and mortality of colorectal cancer in average-risk patients. Please see later in the article for the Editors' Summary.

Original languageEnglish
Article numbere1001352
JournalPLoS Medicine
Volume9
Issue number12
DOIs
StatePublished - Dec 1 2012

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Sigmoidoscopy
Meta-Analysis
Colorectal Neoplasms
Screening
Randomized Controlled Trials
Mortality
Incidence
Gastroenterology
Intention to Treat Analysis
South America
Risk Reduction Behavior
Colonoscopy
Consensus
Databases
Testing

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Effect of Flexible Sigmoidoscopy-Based Screening on Incidence and Mortality of Colorectal Cancer : A Systematic Review and Meta-Analysis of Randomized Controlled Trials. / Elmunzer, B. Joseph; Hayward, Rodney A.; Schoenfeld, Philip S.; Saini, Sameer D.; Deshpande, Amar R; Waljee, Akbar K.

In: PLoS Medicine, Vol. 9, No. 12, e1001352, 01.12.2012.

Research output: Contribution to journalArticle

Elmunzer, B. Joseph ; Hayward, Rodney A. ; Schoenfeld, Philip S. ; Saini, Sameer D. ; Deshpande, Amar R ; Waljee, Akbar K. / Effect of Flexible Sigmoidoscopy-Based Screening on Incidence and Mortality of Colorectal Cancer : A Systematic Review and Meta-Analysis of Randomized Controlled Trials. In: PLoS Medicine. 2012 ; Vol. 9, No. 12.
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abstract = "Background: Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs. Methods and Findings: Medline and Embase databases were searched for eligible articles published between 1966 and 28 May 2012. After screening 3,319 citations and 29 potentially relevant articles, two reviewers identified five RCTs evaluating the effect of FS screening on the incidence and mortality of CRC. The reviewers independently extracted relevant data; discrepancies were resolved by consensus. The quality of included studies was assessed using criteria set out by the Evidence-Based Gastroenterology Steering Group. Random effects meta-analysis was performed. The five RCTs meeting eligibility criteria were determined to be of high methodologic quality and enrolled 416,159 total subjects. Four European studies compared FS to no screening and one study from the United States compared FS to usual care. By intention to treat analysis, FS-based screening was associated with an 18{\%} relative risk reduction in the incidence of CRC (0.82, 95{\%} CI 0.73-0.91, p<0.001, number needed to screen [NNS] to prevent one case of CRC = 361), a 33{\%} reduction in the incidence of left-sided CRC (RR 0.67, 95{\%} CI 0.59-0.76, p<0.001, NNS = 332), and a 28{\%} reduction in the mortality of CRC (relative risk [RR] 0.72, 95{\%} CI 0.65-0.80, p<0.001, NNS = 850). The efficacy estimate, the amount of benefit for those who actually adhered to the recommended treatment, suggested that FS screening reduced CRC incidence by 32{\%} (p<0.001), and CRC-related mortality by 50{\%} (p<0.001). Limitations of this meta-analysis include heterogeneity in the design of the included trials, absence of studies from Africa, Asia, or South America, and lack of studies comparing FS with colonoscopy or stool-based testing. Conclusions: This meta-analysis of randomized controlled trials demonstrates that FS-based screening significantly reduces the incidence and mortality of colorectal cancer in average-risk patients. Please see later in the article for the Editors' Summary.",
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N2 - Background: Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs. Methods and Findings: Medline and Embase databases were searched for eligible articles published between 1966 and 28 May 2012. After screening 3,319 citations and 29 potentially relevant articles, two reviewers identified five RCTs evaluating the effect of FS screening on the incidence and mortality of CRC. The reviewers independently extracted relevant data; discrepancies were resolved by consensus. The quality of included studies was assessed using criteria set out by the Evidence-Based Gastroenterology Steering Group. Random effects meta-analysis was performed. The five RCTs meeting eligibility criteria were determined to be of high methodologic quality and enrolled 416,159 total subjects. Four European studies compared FS to no screening and one study from the United States compared FS to usual care. By intention to treat analysis, FS-based screening was associated with an 18% relative risk reduction in the incidence of CRC (0.82, 95% CI 0.73-0.91, p<0.001, number needed to screen [NNS] to prevent one case of CRC = 361), a 33% reduction in the incidence of left-sided CRC (RR 0.67, 95% CI 0.59-0.76, p<0.001, NNS = 332), and a 28% reduction in the mortality of CRC (relative risk [RR] 0.72, 95% CI 0.65-0.80, p<0.001, NNS = 850). The efficacy estimate, the amount of benefit for those who actually adhered to the recommended treatment, suggested that FS screening reduced CRC incidence by 32% (p<0.001), and CRC-related mortality by 50% (p<0.001). Limitations of this meta-analysis include heterogeneity in the design of the included trials, absence of studies from Africa, Asia, or South America, and lack of studies comparing FS with colonoscopy or stool-based testing. Conclusions: This meta-analysis of randomized controlled trials demonstrates that FS-based screening significantly reduces the incidence and mortality of colorectal cancer in average-risk patients. Please see later in the article for the Editors' Summary.

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