Spatially Fractionated Radiotherapy Versus Conventional Radiotherapy in the Treatment of Soft Tissue Sarcoma

This study is a multicenter, prospective, randomized controlled phase II clinical trial designed to evaluate the efficacy and safety of Spatially Fractionated Radiation Therapy (SFRT) compared to Conventional Radiation Therapy (CRT) in the treatment of soft tissue sarcoma (STS, minimum tumor diameter ≥5 cm). A total of 106 patients were enrolled and randomized in a 1:1 ratio. The primary endpoint is the objective response rate (ORR) of the target lesion at 3, 6, 9, and 12 months post-radiotherapy, assessed using RECIST 1.1 and Choi criteria. Secondary endpoints include the 1-year local control rate (LC) of the target lesion, progression-free survival (PFS), safety (per CTCAE v5.0), and quality of life (QoL, assessed by EORTC QLQ-C30). CRT is delivered at 3.0 Gy per fraction for a total of 15-20 fractions. SFRT comprises CRT at 3.0 Gy per fraction for 15-20 fractions, augmented by weekly high-dose vertices of 8-15 Gy per fraction for 3-4 fractions, aiming to enhance tumor control and potentially stimulate immune responses. This study is a multicenter, prospective, randomized controlled phase II clinical trial designed to evaluate the efficacy and safety of Spatially Fractionated Radiation Therapy (SFRT) compared to Conventional Radiation Therapy (CRT) in the treatment of soft tissue sarcoma (STS, minimum tumor diameter ≥5 cm). A total of 106 patients were enrolled and randomized in a 1:1 ratio. The primary endpoint is the objective response rate (ORR) of the target lesion at 3, 6, 9, and 12 months post-radiotherapy, assessed using RECIST 1.1 and Choi criteria. Secondary endpoints include the 1-year local control rate (LC) of the target lesion, progression-free survival (PFS), safety (per CTCAE v5.0). CRT is delivered at 3.0 Gy per fraction for a total of 15-20 fractions. SFRT comprises CRT at 3.0 Gy per fraction for 15-20 fractions, augmented by weekly high-dose vertices of 8-15 Gy per fraction for 3-4 fractions, aiming to enhance tumor control and potentially stimulate immune responses.

Sex

All

Minimum age

18 Years

Maximum age

70 Years

Inclusion Criteria:

* 1\. Age 18-70 years, irrespective of gender. 2. Pathologically or clinically confirmed diagnosis of soft tissue sarcoma. 3. Minimum tumor diameter ≥5 cm. 4. Receiving systemic treatment as per multidisciplinary team (MDT) recommendations.

  5\. Measurable lesion (per RECIST 1.1/Choi criteria: longest diameter \>1.5 cm, or \>1 cm with two measurable perpendicular diameters).

  6\. ECOG performance status ≤2. 7. Expected survival ≥3 months. 8. Normal liver, kidney, lung, and cardiac function, with tolerance for treatment.

  9\. Patients of childbearing potential agree to use reliable contraception during treatment and for one year thereafter.

  10\. Voluntary provision of signed informed consent.

Exclusion Criteria:

* (1) Patients with a second primary malignancy. (2) Diagnosis of aggressive fibromatosis or rhabdomyosarcoma. (3) Prior radiotherapy to the target lesion. (4) Tumor unsuitable for radiotherapy. (5) Severe liver, kidney, lung, or cardiac dysfunction, precluding tolerance to systemic therapy or radiotherapy.

  (6) Other severe medical conditions that may impact the study (e.g., uncontrolled diabetes, gastric ulcers, or other serious cardiopulmonary diseases).

  (7) Severe or uncontrolled infections, or active autoimmune diseases. (8) Clinically evident central nervous system dysfunction. (9) Pregnant or lactating women, or women of childbearing potential not using contraception.

  (10) Other conditions deemed unsuitable for participation by the investigator.

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