Systematic Review and Meta-Analysis of Natural Orifice Specimen Extraction in Anterior Resection of Rectal Tumors

Background: Despite advancements, specimen extraction through mini-laparotomy in traditional minimally invasive surgery still carries risks of wound-related complications such as infection, incisional hernia, and poor cosmetic results. Natural orifice specimen extraction (NOSE) has been suggested as an alternative to eliminate the need for an abdominal incision, potentially improving postoperative recovery and reducing complications. This systematic review aims to critically compare the clinical and oncologic outcomes of NOSE with conventional laparoscopic anterior resection. Methods: Our search was conducted in line with the most recent Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. An electronic search was conducted of the PubMed and EMBASE databases up to March 2025. Results: After screening, 14 studies including 1149 patients undergoing anterior resection of rectal, sigmoid, and rectosigmoid tumors were included in this review, comprising 502 NOSE and 647 conventional patients. Compared with conventional transabdominal specimen extraction, NOSE was associated with longer operative time (weighted mean difference [WMD]: 12.44 minutes; 95% CI: 1.54–23.35; P = .03), lower estimated blood loss (WMD: −13.75 mL; 95% CI: −25.33 to −2.16; P = .02), and shorter hospital stays (WMD: −0.75 days; 95% CI: −1.03 to −0.48; P < .001). The tumor diameter was smaller in the NOSE cohort (WMD: −0.43 cm; 95% CI: −0.73 to −0.14; P < .01), but there were no significant differences in total lymph node harvest or number of metastatic nodes compared with the conventional approach. Overall complication rates favored NOSE (OR: 0.54; 95% CI: 0.34–0.86; P = .01), driven largely by reduced infections (OR: 0.24; P = .003), while anastomotic leak, hemorrhage, ileus, and reoperation rates did not differ significantly. Conclusions: NOSE is a potential alternative in select patients undergoing anterior resection. However, it is associated with longer operative times, and there is a lack of data on long-term outcomes, such as hernia formation or oncologic safety.