Mini-invasive vs open resection of colorectal cancer and liver metastases: A meta-analysis

BACKGROUND The safety and feasibility of the simultaneous resection of primary colorectal cancer(CRC) and synchronous colorectal liver metastases(SCRLM) have been demonstrated in some studies. Combined resection is expected to be the optimal strategy for patients with CRC and SCRLM. However, traditional laparotomy is traumatic, and the treatment outcome of minimally invasive surgery(MIS) is still obscure.AIM To compare the treatment outcomes of MIS and open surgery(OS) for the simultaneous resection of CRC and SCRLM.METHODS A systematic search through December 22, 2018 was conducted in electronic databases(PubMed, EMBASE, Web of Science, and Cochrane Library). All studies comparing the clinical outcomes of MIS and OS for patients with CRC and SCRLM were included by eligibility criteria. The meta-analysis was performed using Review Manager Software. The quality of the pooled study was assessed using the Newcastle-Ottawa scale. The publication bias was evaluated by a funnel plot and the Begg's and Egger's tests. Fixed-and random-effects models were applied according to heterogeneity.RESULTS Ten retrospective cohort studies involving 502 patients(216 patients in the MIS group and 286 patients in the OS group) were included in this study. MIS was associated with less intraoperative blood loss [weighted mean difference(WMD)=-130.09, 95% confidence interval(CI):-210.95 to-49.23, P = 0.002] and blood transfusion [odds ratio(OR) = 0.53, 95%CI: 0.29 to 0.95, P = 0.03], faster recovery of intestinal function(WMD =-0.88 d, 95%CI:-1.58 to-0.19, P = 0.01) and diet(WMD =-1.54 d, 95%CI:-2.30 to-0.78, P 0.0001), shorter length of postoperative hospital stay(WMD =-4.06 d, 95%CI:-5.95 to-2.18, P 0.0001), and lower rates of surgical complications(OR = 0.60, 95%CI: 0.37 to 0.99, P = 0.04). However, the operation time, rates and severity of overall complications, and rates of general complications showed no significant differences between the MIS and OS groups.Moreover, the overall survival and disease-free survival after MIS were equivalent to those after OS.CONCLUSION Considering the studies included in this meta-analysis, MIS is a safe and effective alternative technique for the simultaneous resection of CRC and SCRLM.Compared with OS, MIS has less intraoperative blood loss and blood transfusion and quicker postoperative recovery. Furthermore, the two groups show equivalent long-term outcomes.