Findings Show Cesium-131 Tiles Enhance the Outcomes in Resected Brain Metastases
Recent findings presented at the 2026 ASCO Annual Meeting highlight significant advancements in the treatment of brain metastases through the use of cesium-131 implants. A pivotal phase III trial demonstrated that these implanted radiation tiles markedly improve local disease control and overall survival rates when compared to standard postoperative stereotactic radiotherapy (SRT).
The study, known as the ROADS trial, enrolled 204 patients with newly diagnosed brain metastases, each measuring between 2 to 7 cm. Participants were randomly assigned to two treatment arms: one receiving immediately implanted cesium-131–containing tiles within the surgical cavity after tumor excision (n = 103), and the other receiving standard SRT, administered two to four weeks post-surgery (n = 101).
The study's main objectives focused on recurrence of the surgical bed and overall survival. After a median follow-up period of 12.9 months, results indicated a significant reduction in local recurrence among patients treated with tile-based radiation. Only 1% of these patients experienced surgical bed recurrence compared to 12% in the SRT group, marking a 94% reduction in the risk of local recurrence. The median time to recurrence was 17.4 months in patients receiving SRT, while the median for the tile group remains undetermined, as more than half of these patients continue to be recurrence-free.
The trial also reported improved recurrence-free survival rates. Median surgical bed recurrence-free survival was noted at 10.9 months for the control group, while the tile group had not reached a median time by the end of the study, indicating significant benefits.
Overall survival rates were notably higher in the tile-treated group, with a 41% reduction in mortality risk. Estimated 2-year survival rates stood at 61.7% for the tile group, compared to 35.7% for those undergoing SRT. The study posits that the earlier resumption of systemic therapy following surgery for the tile group may have contributed to these improved outcomes.
In terms of safety, grade 3 or higher adverse events occurred in 18.1% of the tile group and 19.3% of the SRT group. Moreover, incidences of leptomeningeal disease and radiation necrosis were comparable between the two cohorts.
Further analyses will explore the neurocognitive implications of tile-based treatment, examining memory, attention, and other cognitive functions, along with interactions with systemic cancer therapies.