A Study of Ta-NPs Plus Radiotherapy for Locally Recurrent Retroperitoneal Sarcoma

This prospective, single-arm, open-label phase I study evaluates the safety and tolerability of intratumoral injection of tantalum nanoparticles (Ta-NPs) followed by radiotherapy in patients with locally recurrent retroperitoneal soft tissue sarcoma. Using a standard 3+3 dose-escalation design, three dose levels of Ta-NPs (injection volumes of 2%, 5%, and 10% of tumor volume, all at 30 mg/mL) are tested in sequential cohorts to identify dose-limiting toxicities.