Post-Surgical Stereotactic Radiotherapy (SRT) Versus GammaTile-ROADS (Radiation One and Done Study)

Summary

Objectives

GammaTile therapy results in improved clinical outcomes; however the data is a single site
experience with a limited number of subjects, only 12 of which were patients with metastatic
brain tumors. The primary objective of this randomized, controlled trial is to compare the
efficacy and safety of intraoperative radiation therapy using GammaTilesTM (GT) versus SRT
3-4 weeks following metastatic tumor resection which is the current standard of care. The
data collected in this trial design will allow for a direct comparisons of a variety of
outcomes including local control, overall survival, functional status, quality of life,
neurocognitive status and safety in the target population. In order to support direct
comparisons, subjects will be randomized to the two equally sized arms (1:1) based on the
following stratification factors; age (<60 and =60), duration of extracranial disease control
(=3 months vs >3 months), number of metastases (one vs multiple), histology (lung and
radiation resistant), and the maximal diameter of the index lesion (=3 cm and >3 cm) and use
of prior or current immunotherapy (yes vs no).

An index lesion meeting the criteria of = 2.5cm in maximum diameter and appropriate for gross
total resection (GTR), will be identified and up to three other non-resectable lesions in a
patient will be allowed. After resection of the index lesion, the surgical bed will be
treated with adjunct radiation (either GT or SRT) thereby following the standard of care
guideline. (NCCN Guidelines, 2019). Additional, unresected metastatic lesions will be treated
with stereotactic radiosurgery alone, which also adheres to standard of care guidelines (NCCN
Guidelines, 2019).

GammaTile is an FDA-cleared means of rapid dose delivery of radiation therapy directly to the
tumor bed with predictable dosimetry at the immediate time of re-resection, and a intense but
localized radiation treatment may confer a reduced risk for radiation necrosis compared to
other therapies. It is typically easly placed with minimal additional operative time and
limited staff radiation exposure.

Given these benefits, the rationale for conducting this randomized control comparison study
is to generate additional data, to further support the use of this new FDA-cleared method of
delivering radiation therapy in the setting of newly diagnosed brain metastases.