Proton Irradiation with Hyperthermia in Unresectable Soft Tissue Sarcoma

Area of Science:

• Oncology
• Radiation Oncology
• Medical Physics

Background:

• Unresectable soft tissue sarcomas (STSs) often resist conventional treatments, leading to limb amputation and reduced quality of life.
• Limb-sparing treatments are crucial for maintaining function and improving patient outcomes in STS cases.

Purpose of the Study:

• To evaluate the safety and efficacy of a novel proton thermoradiotherapy approach for unresectable soft tissue sarcomas.
• To assess the potential of combining hyperthermia with proton beam irradiation for improved tumor control and limb preservation.

Main Methods:

• Two patients with unresectable STS of the lower leg received proton irradiation (70-72 Gy RBE) combined with local hyperthermia (39°C-43°C) weekly.
• Treatment was delivered within the HYPROSAR study protocol (NCT01904565), with patients declining amputation.

Main Results:

• Both patients tolerated the proton thermoradiotherapy well, with no significant acute or late treatment-related morbidity.
• Serial MRI revealed a near-complete response of the primary tumors in both individuals.
• At 5 and 14 months post-treatment, patients maintained normal limb function for daily activities.

Conclusions:

• Proton beam irradiation combined with hyperthermia represents a novel and effective cancer therapy approach.
• This initial experience in two unresectable STS patients demonstrates the feasibility, safety, and efficacy of this combined modality for functional limb preservation and tumor control.