ObjectiveTo evaluate effect of RAS gene mutation after liver metastasis resection on overall survival (OS) and disease-free survival (DFS) for patients with colorectal cancer combined with liver metastasis. MethodsA comprehensive and systematic literature search in the PubMed and other databases was conducted, with the final search ending on January 5, 2022. The impact of RAS gene mutation after liver metastasis resection on survival of patients with colorectal cancer combined with liver metastasis was analyzed by the Stata 12.0 software and Review Manager version 5.3 software, meanwhile which were analyzed according to subgroups, including study type (retrospective and prospective studies), region (Asian and European), and number of RAS gene mutation sites (>2 and ≤2). ResultsA total of 26 studies with 13 356 patients were included. The integrated analysis results showed that the patients with RAS mutations had statistically shorter OS [HR=1.54, 95%CI (1.43, 1.65), P<0.001] and DFS [HR=1.32, 95%CI (1.19, 1.44), P<0.001] as compared with RAS wild-type. Except the 1-year overall survival rate, the 2–5-year overall survival rate and 1–5-year disease-free survival rate of patients with RAS gene mutation were statistically lower than those of patients with RAS wild-type (P<0.05). The results of subgroup analysis showed that no matter retrospective and prospective studies, as well as studies in Asian and European countries, it was found that the OS and DFS for patients with RAS gene mutation were shorter than those of patients with wild-type (P<0.05); At the same time, subgroup analysis of the number of RAS gene mutation sites showed that OS and DFS of patients with number of mutation sites >2 were shortened as compared with ≤2 (P<0.05). ConclusionFrom the overall analysis results, the survival of patients with RAS gene mutation after liver metastasis resection is worse than that of patients with RAS wild-type for patients with colorectal cancer combined with liver metastasis.