According to findings from a phase III trial reported by Weinberg et al in the Journal of Clinical Oncology, intraoperative tile-based radiation therapy with cesium-131 significantly improved surgical bed control compared with postoperative stereotactic radiation therapy in patients undergoing resection of newly diagnosed brain metastases. The study also found improved surgical bed recurrence–free survival with tile-based radiation therapy, without apparent increases in radiation necrosis, neurocognitive decline, or deterioration in quality of life.
Study Details
The investigators conducted the ROADS trial (ClinicalTrials.gov identifier NCT04365374) as a prospective, randomized, open-label, noninferiority phase III trial at 32 U.S. centers to compare resection plus postoperative stereotactic radiation therapy, the standard of care following resection of brain metastases, with resection plus tile-based radiation therapy, which delivers focal radiation immediately after resection through permanently implanted collagen tiles containing cesium-131 sources.
Patients had one brain metastasis measuring 2.0 to 7.0 cm requiring resection and could have up to five additional brain metastases not requiring surgery. Before surgery, patients were randomly assigned 1:1 to resection plus tile-based radiation therapy or resection plus stereotactic radiation therapy. In the tile-based radiation therapy group, cesium-131–containing tiles were placed along the resection cavity following intraoperative pathologic confirmation of metastatic disease. In the stereotactic radiation therapy group, cavity radiation was planned as one, three, or five fractions beginning approximately 21 days after surgery.
The co-primary endpoints were time to surgical bed recurrence and surgical bed recurrence–free survival. Of 230 randomly assigned patients, 204 comprised the prespecified modified intent-to-treat population: 103 in the tile-based radiation therapy group and 101 in the stereotactic radiation therapy group. Median follow-up was 12.9 months.
Key Results
Tile-based radiation therapy met criteria for both noninferiority and superiority for the co-primary endpoints. One surgical bed recurrence occurred in the tile-based radiation therapy group compared with 12 in the stereotactic radiation therapy group. Median time to surgical bed recurrence was not reached with tile-based radiation therapy vs 17.4 months with stereotactic radiation therapy (hazard ratio [HR] = 0.06, 95% confidence interval [CI] = 0.01–0.46, P = .0070). At 12 months, the cumulative incidence of surgical bed recurrence was 1.3% vs 15.4%, respectively. Median surgical bed recurrence–free survival was not reached with tile-based radiation therapy vs 10.9 months with stereotactic radiation therapy (HR = 0.48, 95% CI = 0.30–0.76, P = .0021).
Median overall survival was 42.5 months with tile-based radiation therapy vs 17.6 months with stereotactic radiation therapy (HR = 0.59, 95% CI = 0.37–0.96, P = .032). However, the investigators cautioned that this finding requires validation in additional studies.
At 12 months, radiation necrosis occurred in 5.3% of patients receiving tile-based radiation therapy and 5.7% receiving stereotactic radiation therapy. There were no differences in quality of life, functional status, or neurocognitive outcomes. Any adverse event occurred in 79.0% and 80.7% of patients, respectively, and grade 3 or higher treatment-related adverse events occurred in 20.0% and 21.7%.
The investigators concluded: “For patients with newly diagnosed brain metastases requiring resection, [resection with tile-based radiation therapy] significantly improved [time-to-surgical bed recurrence] and [surgical bed recurrence–free survival], demonstrating both non-inferiority and superiority.”
Thomas H. Beckham, MD, PhD, of the University of Texas MD Anderson Cancer Center, Houston, Texas, is the corresponding author for the Journal of Clinical Oncology article.
DISCLOSURE: The study was supported by GT Medical Technologies. For full disclosures of the study authors, visit ascopubs.org.
