Palliative Spatially Fractionated (GRID) Radiotherapy Using Intensity Modulated Proton Therapy

Spatially fractionated radiotherapy (SFRT or GRID) addresses some limitations of traditional stereotactic body radiation therapy by relying on beam collimation to create high-dose "peaks" and intervening low-dose "valleys" throughout the target volume. Standard palliative radiotherapy regimens provide limited durability of response, and there are challenges with delivery to large tumors or in previously irradiated fields. In this study, Proton GRID radiotherapy will be used to deliver three-fraction palliative radiotherapy to patients with tumors needing palliative radiation. The safety and efficacy of this approach will be assessed. It is hypothesized that GRID is highly effective, immunogenic, and associated with low rates of toxicity.

NCT Number	NCT05831579
Lead Sponsor	Washington University School of Medicine
Conditions	Unresectable Solid Tumor, Metastatic Cancer
Enrollment	24 participants
Start Date	2023-05-12
Primary Completion	2027-07-02 (estimated)
Study Completion	2027-07-02 (estimated)
Updated on ClinicalTrials.gov	2026-07-13