Natural orifice versus transabdominal specimen extraction in laparoscopic surgery for colorectal cancer: meta-analysis

BACKGROUND: Natural orifice specimen extraction (NOSE) is a technique that involves collecting a specimen for extraction through a natural opening avoiding a mini-laparotomy incision. The aim of this study was to compare NOSE and transabdominal specimen extraction in laparoscopic (LAP) colorectal cancer surgery for postoperative outcomes and oncological safety. METHOD: A systematic search was conducted in five electronic databases from inception till October 2020. Articles were selected based on the inclusion criteria (studies comparing LAP and NOSE colorectal surgeries reporting at least one of the outcomes) and analysed. Primary outcomes included postoperative complications, pathological results (resection margins and lymph node collection), and oncological outcomes. Secondary outcomes included operating time, blood losses, use of analgesics, functional recovery, duration of hospital stay, and cosmetic results. Fixed and random-effect models were used to measure the pooled estimates. RESULTS: Nineteen studies involving a total of 3432 participants were analysed (3 randomized clinical trials (RCTs) and 16 retrospective non-randomized studies). Pooled results showed significantly reduced postoperative complications (OR 0.54; 95 per cent c.i. 0.44 to 0.67; P < 0.00001). Pathological outcomes of NOSE were comparable to LAP with no significant difference noted in terms of resection margins (P > 0.05) and lymph node collection (weighted mean difference (WMD) −0.47; 95 per cent c.i. −0.94 to 0; P = 0.05). Pooled analysis demonstrated comparable long-term outcomes in terms of cancer recurrence (OR 0.94; 95 per cent c.i. 0.63 to 1.39; P = 0.75), 5-year disease-free survival (HR 0.97; 95 per cent c.i. 0.73 to 1.29; P = 0.83), and overall survival (HR 0.93, 95 per cent c.i. 0.58 to −1.51; P = 0.78). Finally, the NOSE group had decreased use of additional analgesia after surgery and earlier resumption of oral intake when compared with LAP (respectively OR 0.28; 95 per cent c.i. 0.20 to 0.37; P < 0.00001 and WMD −0.35; 95 per cent c.i. −0.54 to −0.15; P = 0.0005). CONCLUSION: This meta-analysis showed that in comparison with LAP, NOSE decreases severe postoperative morbidity while improving postoperative recovery without compromising oncological safety, but it is limited by the small number of RCTs performed in this field.