Natural Orifice Extraction Techniques (Natural Orifice Specimen Extraction and Natural Orifice Transluminal Endoscopic Surgery) for Left-Sided Colorectal Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Purpose: Minimally invasive surgery is the standard approach for colorectal cancers and requires an abdominal incision for specimen removal. Natural orifice specimen extraction (NOSE) may improve outcomes, reducing trauma, and speeding postoperative recovery. This study compares both techniques regarding postoperative complications, operative outcomes, and recurrence.

Methods

We searched PubMed, Scopus, and Cochrane Central Register of Clinical Trials for studies published up to November 2024. Odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs) were pooled using a random-effects model, and heterogeneity was assessed with I2 statistics. Statistical analyses were conducted using R Software version 4.4.1 (R Foundation for Statistical Computing).

Results

Four randomized controlled trials involving 439 patients with colorectal cancer were included, with 212 (48.2%) undergoing NOSE and 227 (51.7%) undergoing conventional laparoscopic specimen extraction. NOSE significantly reduced postoperative pain (visual analog scale score: mean difference [MD] -1.8; 95% confidence interval [CI] -2.5 to -1.1; P = .01), time to pass flatus (MD -0.8; 95% CI -1.1 to -0.6; P < .01), and surgical site infection rates (OR 0.15; 95% CI 0.03-0.69; P = .015) but was associated with a longer operative time (MD 11.1 minutes; 95% CI 1.5-20.6; P = .02). No significant differences were observed between the groups in bowel leaks, lymph nodes harvested, intraoperative blood loss, hospital stay duration, or local recurrence rates.

Conclusion

NOSE was associated with reduced postoperative pain, faster time to pass flatus, and lower infection rates but required longer operative time than conventional laparoscopic specimen extraction. Other outcomes, including complications, operative characteristics, and recurrence, showed no significant differences between the techniques.