CHICAGO — A significant shift in the management of brain metastases may be on the horizon. Findings from the phase III "Radiation One and Done Study" (ROADS), presented at the American Society of Clinical Oncology (ASCO) annual meeting, suggest that a novel approach—implanting radioactive "tiles" immediately after surgical resection—drastically improves local tumor control compared to the current standard of care.
For decades, the standard protocol for patients with large or symptomatic brain metastases has involved a two-step process: surgical resection followed by stereotactic radiotherapy (SRT) administered two to four weeks later. However, the ROADS trial results indicate that this delayed approach may be suboptimal, both logistically and biologically. The use of Cesium-131 collagen tiles, marketed as GammaTile, appears to offer a superior, single-step solution that eliminates the risk of patients missing their follow-up radiation entirely.
The Core Findings: A Paradigm Shift in Local Control
The ROADS trial, which enrolled 230 patients across 32 U.S. centers between 2021 and 2025, sought to determine if "wallpapering" the surgical resection cavity with radioactive tiles could outperform the traditional "wait-and-see" approach to postoperative radiation.
The data presented by Jeffrey Weinberg, MD, of the University of Texas MD Anderson Cancer Center, were stark. The median time to recurrence at the surgical bed was not reached in the patient group treated with Cesium-131 tiles, whereas the control group receiving standard SRT experienced a recurrence median of 17.4 months. The hazard ratio (HR) of 0.06 (95% CI 0.01-0.46, P=0.007) underscores a statistically significant and clinically profound reduction in recurrence risk.
Perhaps most tellingly, the cumulative incidence of recurrence at the cavity site at one year was just 1.3% for the tile-based group, compared to 15.4% for those who waited for traditional SRT. Beyond the primary endpoint of local control, the study also indicated improvements in surgical bed recurrence-free survival (RFS) and overall survival.
"The cancer was less likely to grow back in the treated area, patients were less likely to have negative imaging changes on their follow-up MRI scans, and patients have a lower risk of death," Dr. Weinberg stated during the ASCO press conference. "And this increased efficacy did not come with increased side effects."
Chronology of the ROADS Trial
The ROADS trial was designed to address a persistent logistical and clinical vulnerability in neuro-oncology: the "gap" between surgery and adjuvant radiation.
- 2021–2025 (Enrollment): Over a four-year period, 230 patients with new brain lesions measuring 2 to 7 cm were enrolled.
- The Procedure: For the investigational arm, surgeons placed radioactive tiles (each 2×2 cm) directly onto the edges of the resection cavity immediately following the removal of the tumor. The tiles emit approximately 100–120 Gy at the surface, with 90% of the therapeutic dose delivered within the first five weeks.
- The Control: The standard-of-care group underwent the same surgical resection but was scheduled for traditional SRT 2 to 4 weeks post-surgery.
- Data Analysis: Following the exclusion of patients who did not undergo surgery or were ineligible for other reasons, a modified intent-to-treat population of 204 participants was analyzed.
- ASCO Presentation (2025): The final results were unveiled, showing a significant divergence in outcomes between the two cohorts.
Supporting Data: Why "One and Done" Matters
The logistical hurdles associated with traditional SRT are not merely minor inconveniences; they are major contributors to treatment failure. According to Dr. Weinberg, the risk of local recurrence jumps from 2.3% to nearly 50% if SRT is not administered within the recommended four-week window.
The ROADS trial exposed the fragility of the standard-of-care pathway. In the study, 18 participants in the SRT arm never actually received their scheduled radiation. Reasons for this failure included:
- Prolonged post-operative recovery periods.
- Insurance authorization and administrative delays.
- Logistical barriers, such as weather events or transport issues.
- Patient or investigator decisions to forgo further treatment.
By contrast, the tile-based approach ensures 100% treatment compliance because the radiation is delivered before the patient ever leaves the operating room. Furthermore, there is a biological hypothesis: by applying radiation at the precise moment the cavity is created, surgeons can neutralize microscopic tumor cells before they have the opportunity to proliferate or migrate, a phenomenon that may be hindered by a 2-to-4-week delay.
Official Responses and Expert Scrutiny
While the oncology community has largely received the findings with enthusiasm, there is a healthy degree of academic caution regarding the study’s broader implications.
David Schiff, MD, of the University of Virginia School of Medicine, served as the ASCO-designated expert to comment on the trial. While he acknowledged the potential for a "new standard of care," he pointed to several areas requiring closer inspection.
"The final issue that I’m struggling with is the overall survival results," Dr. Schiff noted. "These overall survival results aren’t easily explained, and that potentially suggests some imbalance in patient characteristics between the two groups."
Dr. Schiff also raised concerns regarding post-randomization exclusions and the lack of granular patient data, which can sometimes skew the results in favor of an investigational therapy. He reminded the audience that in many cases of metastatic cancer, overall survival is dictated more by systemic disease control—the body’s response to the primary cancer—than by the local management of a single brain lesion.
Dr. Weinberg acknowledged that the trial was not specifically powered to prove a mortality benefit, advising that the survival statistics be viewed as encouraging indicators rather than definitive proof of a life-prolonging effect.
Implications for Future Practice
If these findings hold up in real-world clinical practice, the implications for neuro-oncology could be sweeping. Currently, 150 U.S. centers are credentialed to place the radioactive tiles, suggesting that the infrastructure for a rapid transition to this method already exists.
Safety Profile
One of the most reassuring aspects of the ROADS data is the safety profile. Concerns regarding radiation necrosis—a common and debilitating side effect of intensive brain radiation—were addressed head-on. The study found no significant difference in the frequency of radiation necrosis or leptomeningeal disease between the two groups. Grade 3 or higher adverse events occurred in 18% of the tile-based group and 19% of the SRT group, confirming that the "wallpapering" method does not introduce additional toxicity.
A Multidisciplinary Future
The success of the tile-based approach emphasizes the importance of the multidisciplinary team. The process requires seamless coordination between neurosurgeons, who place the tiles, and radiation oncologists, who perform the preoperative mapping and postoperative dose planning.
"This benefit is both a logistical one and seems to be a biological one," Dr. Weinberg said. "Being able to target the walls of the resection cavity right as they’re rolling out of the operating room provides a level of precision and reliability we haven’t been able to consistently achieve with traditional SRT."
As the medical community digests the ROADS trial data, the focus will likely shift toward long-term follow-up and cost-effectiveness analyses. If the tiles prove to be as robust in general practice as they were in the trial, the "wait-and-see" window that has defined post-operative brain tumor care for decades may soon be closed for good.
