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

Inclusion criteria

• Age: 18-75 years old, both genders are eligible.
• Pathological Diagnosis: Histologically confirmed soft tissue sarcoma, including but not limited to:

• Undifferentiated pleomorphic sarcoma
• Liposarcoma
• Leiomyosarcoma
• Synovial sarcoma
• Fibrosarcoma
• Other high-grade soft tissue sarcomas
• Disease Stage:

• Locally advanced, unresectable soft tissue sarcoma, or
• Recurrent or metastatic soft tissue sarcoma
• Prior Therapy:

• Prior surgery, radiotherapy, or chemotherapy is allowed.
• At least 4 weeks since the last anti-tumor treatment.
• Prior treatment-related toxicities have resolved to ≤Grade 1 (except alopecia).
• Measurable Disease: At least one measurable lesion according to RECIST 1.1 criteria.
• Performance Status: ECOG performance status score of 0-2.
• Life Expectancy: ≥3 months.
• Organ Function:

• Hematology: Hemoglobin ≥50 g/L, absolute neutrophil count ≥1.5×10⁹/L, platelet count ≥60×10⁹/L
• Liver Function: Total bilirubin ≤1.5× upper limit of normal (ULN), ALT and AST ≤2.5× ULN (≤5× ULN for patients with liver metastasis)
• Renal Function: Serum creatinine ≤1.5× ULN or creatinine clearance ≥50 mL/min
• Cardiac Function: Left ventricular ejection fraction ≥40%
• Informed Consent: The patient or their legal representative has signed the informed consent form.

Exclusion criteria

• Special Types of Sarcoma:

• Gastrointestinal Stromal Tumor (GIST)
• Osteosarcoma
• Ewing's Sarcoma
• Prior Treatment History:

• Previous radiotherapy to the same site with a cumulative dose that may exceed the normal tissue tolerance dose
• Major surgery within 4 weeks
• Concurrent Diseases:

• Active autoimmune diseases
• Diseases requiring systemic immunosuppressive therapy
• Severe cardiovascular diseases (myocardial infarction, unstable angina, heart failure, etc.)
• Severe pulmonary diseases (interstitial pneumonia, pulmonary fibrosis, etc.)
• Active infections requiring systemic anti-infective therapy
• Central Nervous System Metastasis: Symptomatic brain or spinal metastasis.
• Pregnancy and Lactation: Women who are pregnant or breastfeeding.
• Allergy History: Known allergies to the drugs or their components involved in the study.