eP347 - Natural Orifice Specimen Extraction versus Conventional Laparoscopy for Left-Sided Colorectal Carcinoma: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Purpose/Background: The Natural Orifice Specimen Extraction (NOSES) technique avoids a mini-laparotomy, which could improve post-operative outcomes. Previous Meta-analysis investigated this technique for colorectal cancer but with higher risk of bias by including mostly observational studies and by mixing benign and malignant indications for surgery, as well as right and left sided procedures. We aim to improve the evidence on this topic by conducting an analysis exclusively of RCT that compares the use of NOSES to conventional laparoscopy (CL) for left-sided colorectal carcinoma (CRC).Methods/Interventions: A systematic search was conducted on PubMed, Embase and Cochrane’s Central from their inception until July, 2023. Studies were screened independently by two authors and discordances were solved through a consensus. Only RCTs comparing NOSES to CL in the left-sided CRC were included. The primary outcome investigated was anastomotic leak. Secondary outcomes were intraoperative blood loss, hospital length of stay, wound infection occurrence, time to passage of flatus, operating time, and lymph nodes harvested. Statistical analysis was performed using Review Manager 5.4.1 with a random-effects model. To assess risk of bias, the Cochrane’s Risk of Bias 2 score (RoB-2) was used. This study followed PRISMA guidelines and Cochrane’s recommendations.Results/Outcomes: Out of 805 studies, we included 4 RCTs with 470 patients. Despite three of these being considered at low risk of bias, the other study was classified as some concerns on RoB-2 due to its randomization process. The NOSES group had less intraoperative blood loss (MD= -17.73; 95% CI -29.26— -6.19; p=0.003; figure 1A), shorter hospital stay (MD= -0.74; 95% CI -1.48— -0.01; p=0.05; figure 1B), less wound infections (RR= 0.13; 95% CI 0.04—0.5; p=0.003; figure 1C), and quicker time to passage of flatus (MD= -18.5; 95%CI -20.07— -16.94; p < 0.01; figure 1D) . There was no statistically significant difference regarding operating time (MD 7.26; 95% CI -4.56—19.09; p=0.23; figure 1E); anastomotic leak (OR= 1.42; 95%CI 0.5—4.05; p=0.51; figure 1F) and number of lymph nodes harvested (MD -0.86; 95% CI -2.49—0.76; p=0.3; figure 1G). Pooled analysis showed failure to extract the specimen through the natural orifice in 9.3% of cases.Conclusion/

Discussion: This comprehensive systematic review and meta-analysis provides evidence that NOSES has benefits over CL for left-sided CRC regarding blood loss, hospital length of stay, wound infections and passage of flatus. Despite its safety and viability, larger trials with longer follow-ups are needed for more robust evidence in the topic."Forest plots of outcomes

Forest plots of outcomes
PRISMA Flowchart of study Screening

PRISMA Flowchart of study
Risk of Bias

RoB-2 "