Objective:To evaluate the efficacy and safety of radiotherapy as a combined mode with in-situ vaccine for patients with advanced soft tissue sarcoma(STS).Methods:The clinical data of 12 patients with advanced STS who received combination therapy mode at the Cancer Center of Gulou Hospital Affiliated to the School of Medicine of Nanjing University between December 2020 and September 2024 were retrospectively analyzed.All 12 patients received combined therapy.The main radiotherapeutic approach was hypofractionated radiotherapy.The targeted therapy mainly involved Anlotinib(in 10 cases)or Apatinib(in 2 cases).Immunotherapy mainly involved PD-1 antibodies.The primary endpoint was disease control rate(DCR),and the secondary endpoints were objective response rate(ORR)and safety.Results:Among the 12 STS patients who received combined treatment,0 cases achieved CR,4 cases achieved PR;7 cases had SD,and 1 case had PD.The ORR was 33%,and the DCR was 91.7%,among which the DCR of the target lesions was 100%.Among the 12 patients,9 patients experienced grade Ⅰ to grade Ⅱ adverse reactions.The most frequently occurring hematological adverse reactions were anemia(6 cases)and abnormal results of liver function tests(3 cases).The most frequently occurring non-hematological adverse reactions were proteinuria(5 cases),hypertension(4 cases),abnormal thyroid function(3 cases),anorexia(3 cases),and nausea and vomiting(2 cases).Only 2 cases had grade Ⅲ hematological toxicity,and 1 case had grade Ⅲpneumothorax.Conclusion:Radiotherapy as a combined therapy mode with in situ vaccine can achieve a higher DCR in advanced soft tissue sarcomas without serious adverse reactions.This combined treatment modality demonstrates good efficacy and safety.