In patients with nonmalignant findings, colorectal cancer incidence and mortality rates were found to be significantly lower after colonoscopy when researchers conducted a meta-analysis of observational studies. The incidence and mortality rates were even lower after screening colonoscopy in the general population.
“[This study] provides additional evidence for the effectiveness of colonoscopy in the general population,” the researchers wrote.
Researchers examined PubMed, Embase and conference abstracts that were published through April 2015, and included 11 studies with 1,499,521 patients in the analysis. Overall CRC incidence and mortality were the primary outcomes. Using random-effect models, pooled RRs and 95% CIs were determined.
Significant associations were found between colonoscopy in patients with nonmalignant findings and reductions in both CRC incidence (61% reduction; RR = 0.39; 95% CI, 0.26-0.6) and mortality (61% reduction; RR = 0.39; 95% CI, 0.35-0.43).
On further analysis, screening colonoscopy showed even greater reductions in CRC incidence (89% reduction; RR = 0.11; 95% CI, 0.08-0.15) vs. diagnostic colonoscopy (RR = 0.51; 95% CI, 0.43-0.59).
Colonoscopy showed similar protection for men (RR = 0.36; 95% CI, 0.32-0.4) and women (RR = 0.23; 95% CI, 0.1-0.54). However, colonoscopy was less protective in cases of proximal CRC mortality (RR = 0.57; 95% CI, 0.52-0.63) vs. distal CRC (RR = 0.18; 95% CI, 0.11-0.31).
“When interpreting the study results, both the overall effect of colonoscopy and the individual effect of screening colonoscopy derived from subgroup analysis are informative,” the researchers wrote. “As regular colonoscopy screening has not been implemented even in many developed countries, the primary outcome, which estimated the benefit derived from both screening and diagnostic colonoscopies, reflected the effect of regular colonoscopy in routine clinical practice. Subgroup analysis of screening colonoscopy provides data on the maximum cases of CRCs and CRC-related deaths that may be prevented in patients with nonmalignant findings by population-based screening programs in standardized conditions, which is more important from a public health perspective.” – by Suzanne Reist
Disclosure: The researchers report no relevant financial disclosures.