AbstractBackgroundFew studies have investigated the efficacy of comprehensive therapies, including immunotherapy, for gastric cancer with synchronous liver metastases (GCLM). We retrospectively compared the effect of immunochemotherapy and chemotherapy alone as conversion therapies on the oncological outcomes of patients with GCLM.MethodsThe clinicopathological data of 100 patients with GCLM from February 2017 to October 2021 at our institution were retrospectively analyzed. Patients were divided into immunochemotherapy (n= 33) and chemotherapy‐alone (n= 67) groups.ResultsBaseline clinicopathological data did not differ significantly between the two groups. The immunochemotherapy group had a higher overall response rate (59.4% vs. 44.0%,p= 0.029) and disease control rate (71.9% vs. 49.2%,p= 0.036) than the chemotherapy group. The immunochemotherapy group showed better tumor regression in the gastric mass, metastatic lymph nodes, and liver lesions than the chemotherapy group. Ten (30.3%) patients in the immunochemotherapy group and 13 (19.4%) patients in the chemotherapy group underwent surgery after conversion therapy. However, the difference was not statistically significant. The overall survival (OS) and progression‐free survival (PFS) rates were better in the immunochemotherapy group than in the chemotherapy group. Treatment‐related adverse events occurred in 24 (72.7%) and 47 (70.1%) patients in the immunochemotherapy and chemotherapy groups, respectively.ConclusionsAs a conversion therapy for GCLM, immunotherapy yielded better primary and metastatic tumor regression and survival benefits, with no increase in adverse events compared to chemotherapy.