Long-term outcomes after different treatments for gastric cancer with synchronous liver metastasis A PRISMA systematic review and network meta-analysis

Background: The treatment of gastric cancer (GC) with synchronous liver metastasis is still controversial. This systematic review and network meta-analysis was designed to evaluate the long-term outcomes after different treatments of GC with synchronous liver metastasis. Methods: Several electronic databases were searched to identify eligible studies updated on May 1, 2021. Studies assessing the overall survival (OS) after different treatments (including chemotherapy, interventional therapy, surgical therapy alone and adjunctive therapy after surgery) of GC with synchronous liver metastasis were included. Odds ratios with 95% confidence interval (CI) were calculated for survival variables. Results: A total of 15 studies including 4312 patients were included in this network meta-analysis. Adjunctive therapy after surgery performed better than surgery therapy alone (hazard ratio [HR]= 1.23, 95% credible interval [CrI]: 0.69-2.17), chemotherapy (HR= 1.18, 95%CrI: 0.71-1.95), and interventional therapy in terms of 1-year OS (HR= 2.03, 95%CrI: 1.22-3.37). In terms of 3-OS, adjunctive therapy after surgery showed better efficacy than surgery therapy alone (HR= 1.48, 95%CrI: 0.40-5.47), chemotherapy (HR= 1.27, 95%CrI: 0.37-4.35), and interventional therapy (HR= 3.16, 95%CrI: 0.73-13.63). For 5-OS, adjunctive therapy after surgery was superior to surgery therapy alone (HR= 1.74, 95%CrI: 0.08-37.76), chemotherapy (HR= 1.44, 95%CrI: 0.66-3.14), and interventional therapy (HR= 1.46, 95%CrI: 0.06-34.36). There were no statistical inconsistency and small-study effect existed in our network meta-analysis for 1-year, 3-year, or 5-year OS. Cluster ranking analysis performed with surface under the cumulative ranking showed adjuvant therapies after surgery (99.9, 96.7, 90.2) ranking higher than surgery therapy alone, chemotherapy, and interventional therapy for 1-year, 3-year, 5-year OS. Conclusion: The OS of adjuvant therapy after surgery was better than that of surgery therapy alone, chemotherapy, and interventional therapy. Adjuvant therapy after surgery is the most recommended therapy for people with GC with synchronous liver metastasis.