Space-making Particle Therapy Using Bioabsorbable Spacer for Bone and Soft Tissue Sarcomas: Two-institution...

Area of Science:

• Oncology
• Radiation Oncology
• Surgical Oncology

Background:

• Particle therapy for bone and soft tissue sarcomas (BSTSs) is challenging when tumors are near critical organs like the intestine.
• Space-making particle therapy (SMPT) utilizing a bioabsorbable spacer (BAS) presents a potential solution to overcome these limitations.

Purpose of the Study:

• To evaluate the efficacy and safety of SMPT with a BAS for treating BSTSs located near the intestine.
• To analyze patient outcomes, including survival rates and adverse events, associated with this novel treatment approach.

Main Methods:

• Retrospective analysis of 28 patients treated with SMPT and BAS between November 2019 and August 2023.
• Kaplan-Meier method and log-rank test were used for outcome and association analysis.
• Adverse events were assessed using the Common Terminology Criteria for Adverse Events (CTCAE) v5.0.

Main Results:

• The 3-year overall survival, progression-free survival, and local control rates were 83%, 63%, and 80%, respectively.
• Pelvic tumor location and less aggressive sarcoma types (chordoma, Ewing sarcoma) were linked to improved progression-free survival.
• Adverse events related to the BAS were infrequent (e.g., grade 2 constipation in 7%), with manageable radiation toxicities.

Conclusions:

• SMPT with a BAS is a safe and effective strategy for treating BSTSs near critical organs.
• This approach facilitates curative radiation doses with minimal toxicity.
• Further long-term follow-up is necessary to fully ascertain the enduring outcomes.