Meta-Analysis
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World J Gastroenterol. Dec 28, 2014; 20(48): 18466-18476
Published online Dec 28, 2014. doi: 10.3748/wjg.v20.i48.18466
Reduced incidence and mortality from colorectal cancer with flexible-sigmoidoscopy screening: A meta-analysis
Jennifer Shroff, Nirav Thosani, Sachin Batra, Harminder Singh, Sushovan Guha
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
Harminder Singh, Departments of Internal Medicine and Community Health Sciences and IBD Clinical and Research Centre, University of Manitoba, Winnipeg MB R3T 2N, Canada
Author contributions: Shroff J contributed to acquisition of data, analysis and interpretation of data, and drafting of manuscript; Thosani N and Guha S contributed to concept and study design, acquisition of data, analysis and interpretation of data, statistical analysis, and drafting of manuscript; Batra S and Singh H contributed to acquisition of data, analysis and interpretation of data, statistical analysis, and drafting of manuscript; and Guha S contributed to drafting of manuscript, critical revision of manuscript for important intellectual content, statistical analysis, administrative, technical, or material support and supervision.
Correspondence to: Sushovan Guha, MD, PhD, Division of Gastroenterology, Hepatology, and Nutrition, MSB 4.234, 6431 Fannin Street, Houston, TX 77030, United States. sushovan.guha@uth.tmc.edu
Telephone: +1-713-5006677 Fax: +1-713-5006699
Received: January 23, 2014
Revised: February 24, 2014
Accepted: April 5, 2014
Published online: December 28, 2014
Abstract

AIM: 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).

CONCLUSION: 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.

Keywords: Colorectal Cancer, Flexible sigmoidoscopy, Randomized control trials, Meta-analysis, Mortality, Incidence

Core tip: This meta-analysis confirms that screening flexible sigmoidoscopy (FS) reduces the overall incidence of and mortality from colorectal cancer (CRC). In addition, FS reduces the incidence of and mortality from distal CRC, incidence of proximal CRC, and decreases the likelihood of subsequent diagnosis of advanced CRC. We believe, based on the proven benefits of FS, lower rates of complications with FS than with colonoscopy and feasibility in clinical practice, FS should be offered as an option for CRC screening, particularly in the population-based CRC screening programs.