Rigid or Flexible Sigmoidoscopy in Colorectal Clinics? Appraisal Through a Systematic Review and Meta-analysis

Aim: Rigid sigmoidoscopy is sometimes performed at first presentation in colorectal clinics. We assessed the feasibility of flexible sigmoidoscopy in similar situations by comparing it with rigid sigmoidoscopy as a first investigative tool. Methods: The Medline, Embase, and Cochrane databases were searched for randomized and non-randomized clinical trials comparing the usefulness of rigid and flexible sigmoidoscopy. The risk difference (RD) and weighted mean difference (WMD) were calculated for the cancers/abnormalities detected and discomfort associated with the procedure, respectively. The standard mean difference (SMD) was calculated for the depth of examination and duration of the procedure. Results: Flexible sigmoidoscopy had a significantly higher rate of detection of cancers and total abnormalities (RD of 0.020 and 0.138 and 95% confidence interval [CI] of 0.006-0.034 and 0.077-0.200, respectively), and rigid sigmoidoscopy caused significantly more patient discomfort (WMD of 0.981 and 95% CI of 0.693-1.269). Flexible sigmoidoscopy provided significantly greater depth of examination (SMD of 3.175, 95% CI of 2.397-3.954), and rigid sigmoidoscopy required less time (SMD of -1.601, 95% CI of -2.728 to -0.474). Conclusions: Flexible sigmoidoscopy is a better investigative tool in colorectal clinics than the rigid sigmoidoscopy. Implementation of this idea can help in early diagnosis at first presentation and can certainly expedite the management of colorectal malignancies.