The natural orifice specimen extraction surgery compared with conventional laparoscopy for colorectal cancer: A meta-analysis of efficacy and long-term oncological outcomes

Purpose Natural orifice specimen extraction surgery (NOSES) has gradually become established in treating colorectal cancer. This meta-analysis assesses NOSES in the treatment of colorectal cancer compared with conventional laparoscopy (CL) and determines the effect of long-term prognosis. Methods Various medical databases were searched up to May 2021. We included retrospective and randomized trials on the treatment of colorectal cancer with NOSES. Pooled weighted/standardized mean differences (WMD/SMD), odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals (CIs) were calculated using either fixed- or random-effects models. STATA was conducted for the meta-analysis. Results This meta-analysis included 16 studies comprising 2266 patients. Compared with CL, NOSES had more benefits in terms of overall postoperative complications (OR = 0.47, 95%CI [0.35,0.64]; Z = 4.91, P < 0.001), incision-related complications (OR = 0.15, 95%CI [0.07,0.31]; Z = 4.97, P < 0.001), time to first flatus (SMD = −0.58, 95%CI [-0.68,-0.48]; Z = 11.21, P < 0.001), hospital stay (WMD = −1.03, 95%CI [-1.55,-0.51]; Z = 3.86, P < 0.001), cosmetic scores (WMD = 1.37, 95%CI [0.59,2.14]; Z = 3.47, P = 0.001), the visual analogue scale on postoperative day 1 (WMD = −1.46, 95%CI [-2.39,-0.52]; Z = 3.06, P = 0.002), additional analgesics usage (OR = 0.33, 95%CI [0.26, 0.43]; Z = 8.43, P < 0.001), whereas the operative time of NOSES was prolonged (WMD = 13.09, 95%CI [7.07,19.11]; Z = 4.26, P < 0.001). Postoperative anastomotic complications, intra-abdominal infection, pelvic floor function, intraoperative blood loss, number of lymph node dissection, 3-year disease-free and overall survival in the NOSES group were comparable with those in the CL group. Conclusions NOSES is a safe and reliable surgical procedure for the treatment of colorectal cancer and provides good long-term oncological outcomes. Large-scale multicenter studies are required to confirm its clinical benefits. Highlights Natural orifice specimen extraction surgery (NOSES) is a technique for extracting specimens from natural orifices (such as anus or vagina). NOSES can significantly reduce the postoperative complications, especially incision-related complications. NOSES can accelerate the postoperative recovery of patients. Long-term prognosis with NOSES was generally satisfactory.