Minimally invasive versus open hepatectomy for the resection of colorectal liver metastases: a systematic review and meta-analysis

Background: While surgical resection has a demonstrated utility for patients with colorectal liver metastases (CRLM), it is unclear whether minimally invasive surgery (MIS) or an open approach should be used. This review sought to assess the efficacy and safety of MIS versus open hepatectomy for isolated, resectable CRLM when performed separately from (Key Question (KQ) 1) or simultaneously with (KQ2) the resection of the primary tumor. Methods: PubMed, Embase, Google Scholar, Cochrane CENTRAL, International Clinical Trials Registry Platform (ICTRP), and ClinicalTrials.gov databases were searched to identify both randomized controlled trials (RCTs) and non-randomized comparative studies published during January 2000-September 2020. Two independent reviewers screened literature for eligibility, extracted data from included studies, and assessed internal validity using the Cochrane Risk of Bias 2.0 Tool and the Newcastle-Ottawa Scale. A random-effects meta-analysis was performed using risk ratios (RR) and mean differences (MD). Results: From 2304 publications, 35 studies were included for meta-analysis. For staged resections, three RCTs and 20 observational studies were included. Data from RCTs indicated MIS having similar disease-free survival (DFS) at 1-year (RR 1.03, 95%CI 0.70-1.50), overall survival (OS) at 5-years (RR 1.04, 95%CI 0.84-1.28), fewer complications of Clavien-Dindo Grade III (RR 0.62, 95%CI 0.38-1.00), and shorter hospital length of stay (LOS) (MD -6.6 days, 95%CI -10.2, -3.0). For simultaneous resections, 12 observational studies were included. There was no evidence of a difference between MIS and the open group for DFS-1-year, OS-5-year, complications, R0 resections, blood transfusions, along with lower blood loss (MD -177.35 mL, 95%CI -273.17, -81.53) and shorter LOS (MD -3.0 days, 95%CI -3.82, -2.17). Conclusions: Current evidence regarding the optimal approach for CRLM resection demonstrates similar oncologic outcomes between MIS and open techniques, however MIS hepatectomy had a shorter LOS, lower blood loss and complication rate, for both staged and simultaneous resections. Keywords: Colorectal cancer; Laparoscopic hepatectomy; Laparoscopic surgery; Liver tumor; Metastasectomy; Minimally invasive surgery