A Prospective, Multicenter, Open-label, Single-arm Phase II Clinical Study Evaluating the Efficacy and Safety of Spatially Fractionated Radiotherapy Combined With the PraG Strategy for the Treatment of Soft Tissue Sarcoma

The primary objective of this clinical trial is to evaluate the efficacy and safety of spatially fractionated radiotherapy combined with the PraG strategy in the treatment of soft tissue sarcoma (STS). The main questions it aims to answer are: 1. Can spatially fractionated radiotherapy combined with the PraG strategy improve the clinical prognosis of patients? 2. What medical adverse events and clinical problems will participants encounter during the treatment with spatially fractionated radiotherapy combined with the PraG strategy? Researchers will administer a combined therapeutic regimen consisting of spatially fractionated radiotherapy, Toripalimab, recombinant human granulocyte-macrophage colony-stimulating factor injection, and Thymalfasin injection to enrolled patients, so as to observe the efficacy and safety of this therapeutic strategy for soft tissue sarcoma. Participants will: 1. The treatment will be divided into two major phases: the radiotherapy phase and the immunotherapy phase, with concomitant immunomodulatory supportive therapy administered throughout the entire treatment course. 2. The total duration of treatment will last for 1 year starting from the first dose of medication, with regular clinical evaluations conducted according to the individual disease characteristics of each patient. 3. Participants will receive daily oral administration of ABC or placebo for a consecutive 4 months. 4. Routine follow-up examinations will be performed at an interval of 8/12 weeks. 5. Clinical symptoms, imaging indicators, biochemical parameters and survival status of all participants will be systematically recorded and documented throughout the study period.