NCT06857006

Trial of Differential Margins in Single Isocenter Radiosurgery of Brain Metastases

UAB 2507 - Randomized Phase II Study of Differential Margins in Single Isocenter Radiosurgery of Brain Metastases

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 180 (estimated)
• Sponsor: University of Alabama at Birmingham · Academic / Other
• Sex: All
• Age: 19 Years
• Healthy volunteers: Not accepted

Summary

Radiosurgery is the use of a focal high dose of radiation therapy to ablate or kill a tumor. This trial will enroll patients with brain metastases 4 cm or less in greatest diameter and will compare 0mm margin to a 2mm margin for treatment.

Detailed description

Without a stereotactic frame there is considerable variation in practice in the use of planning target volume (PTV) margins for linac radiosurgery. In particular, the use of a single isocenter for multiple targets geometrically increases the risk that rotational errors will result in significant dosimetric errors, and many centers have considered adding margin. A recent AAPM task group survey has found that \~90% of centers worldwide add a PTV margin to account for error and that 8% add more than 2 mm. The most common margin is 2 mm. Other potential reasons to add a margin include spacial MRI error, couch walkout, CBCT to linac isocenter mismatch, and undetected intrafraction motion. Treatment volume is the greatest predictor of radiation toxicity associated with radiosurgery and potentially unnecessary margins will lead to increased risk to the patient. This trial will incorporate a composite endpoint that includes control of the tumor and toxicity. Uncomplicated tumor control probability (UTCP) is defined as the chance the tumor is locally controlled (TCP) without grade 3 or greater CNS toxicity (1-NTCP). The investigators hypothesize a 2 mm margin will worsen uncomplicated control compared to a 0 mm PTV margin in the treatment multiple metastases in a single fraction. This trial will inform the standard of care margin (0 mm vs 2 mm) for single isocenter treatment of multiple targets.

Conditions

• Brain Metastases

Interventions

Type	Name	Description
PROCEDURE	brain metastases radiosurgery	Radiosurgery is the use of a focal high dose of radiation therapy to ablate or kill a tumor. This trial will enroll patients with brain metastases 4 cm or less in greatest diameter and will compare 0mm margin to a 2mm margin for treatment.

Timeline

• Start date: 2025-04-08
• Primary completion: 2028-06-01
• Completion: 2028-08-01
• First posted: 2025-03-04
• Last updated: 2025-10-15

Locations

1 site across 1 country: United States