Improved local control using higher dose SBRT in metastatic sarcoma patients

Area of Science:

• Oncology
• Radiation Oncology
• Medical Physics

Background:

• Stereotactic Body Radiotherapy (SBRT) is a viable alternative to surgery for metastatic sarcoma.
• Limited data exists on the specific dose-response relationship for SBRT in sarcoma metastases.
• This study investigates the efficacy and dose-response of SBRT in metastatic sarcoma patients.

Purpose of the Study:

• To analyze the efficacy of Stereotactic Body Radiotherapy (SBRT) in patients with metastatic sarcoma.
• To establish the dose-response relationship between SBRT and tumor control.
• To evaluate survival outcomes and adverse events associated with SBRT for sarcoma metastases.

Main Methods:

• Retrospective analysis of 43 patients with 83 metastatic sarcoma lesions treated with SBRT (2008-2021).
• SBRT utilized inhomogeneous dose distribution with higher doses in the planning target volume (PTV).
• Assessed local control (LC), progression-free survival (PFS), overall survival (OS), and adverse events; statistical analysis performed.

Main Results:

• Excellent 1, 2, and 5-year local control rates of 97%, 93%, and 84% respectively.
• Tumors receiving higher planned mean CTV doses (EQD2 ≥ 278.8 Gy) showed significantly improved LC (100% at 1-2 years, 93% at 5 years) compared to lower doses (p < 0.001).
• Median overall survival was 43 months with limited mild adverse events.

Conclusions:

• A significant dose-response relationship exists for SBRT in metastatic sarcoma, with higher doses yielding superior local control.
• SBRT is an effective treatment for metastatic sarcoma, offering excellent LC and manageable toxicity.
• The inhomogeneous dose distribution in SBRT may contribute to these favorable outcomes.