Safety and long-term prognosis of simultaneous versus staged resection in synchronous colorectal cancer with liver metastasis: a systematic review and meta-analysis

PURPOSE: The optimal time point for surgical resection of synchronous colorectal liver metastases (SCLMs) is still controversial. This meta-analysis evaluated the safety and long-term prognoses of simultaneous and staged resection of SCLM to provide a reference for clinical selection. METHODS: A systematic literature search for studies published by October 2022 was performed using PubMed, Web of Science, Embase, Scopus and Cochrane Library. The evaluated outcome parameters were total, gastrointestinal and hepatic complications, as well as perioperative mortality, intraoperative blood loss, total hospital stay, 5-year disease-free survival (DFS) and 5-year overall survival (OS). RESULTS: This meta-analysis included 22 nonrandomised and one randomised study comprising 4862 patients. The patients undergoing simultaneous resection of SCLM had similar total (OR = 0.88, 95% CI [0.66–1.19], P = 0.409), gastrointestinal (OR = 1.19, 95% CI [0.89–1.59], P = 0.241) and hepatic (OR = 1.04, 95% CI [0.83–1.31], P = 0.734) complications, as well as perioperative mortality (OR = 1.79, 95% CI [0.88–3.64], P = 0.108), 5-year DFS (HR = 1.26, 95% CI [0.96–1.66], P = 0.098) and 5-year OS (HR = 1.13, 95% CI [0.95–1.34], P = 0.164). Lower intraoperative blood loss (SMD = − 0.39, 95% CI [− 0.60 to − 0.18], P < 0.001) and shorter total hospital stay (WMD = − 5.43, 95% CI [− 7.29 to − 3.58], P < 0.001) were observed in the simultaneous-resection group versus the staged group. CONCLUSIONS: Simultaneous resection is safe and effective for SCLM patients. The long-term prognosis is equivalent to that of the traditional staged resection. Correct selection of resectable SCLM patients for the simultaneous resection of the primary tumour and liver metastases can be the first choice. Owing to the potential heterogeneity, more RCTs should be included to verify our conclusions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40001-022-00937-z.