GammaTile Improves Metastatic Brain Tumor Outcomes Without Added Toxicity: Jeffrey Weinberg, MD

Intraoperative cesium-131 tile-based radiation therapy (TBRT) with GammaTile significantly improved local control, surgical bed recurrence-free survival (SB-RFS), and overall survival (OS) compared with post-operative stereotactic radiotherapy (SRT), with equivalent safety, according to final results from the phase 3 ROADS trial (NCT04365374) presented at the 2026 annual meeting of the American Society of Clinical Oncology.

In an interview with The American Journal of Managed Care^®, Jeffrey Weinberg, MD, professor of neurosurgery at MD Anderson Cancer Center and lead researcher on the ROADS trial, explained what the trial data shows and what this means for the treatment of newly diagnosed metastatic brain tumors going forward.

What the ROADS Trial Found

The open-label trial randomized 230 patients with newly diagnosed brain metastases planned for surgical resection 1:1 at 32 US centers to surgery plus SRT or surgery plus TBRT. Surgical bed recurrence (SBR) occurred in 11.9% of SRT patients vs just 1.0% in the TBRT arm. Median time to SBR was 17.4 months in the SRT arm and was not reached in the TBRT arm (HR, 0.06; P = .007). Similarly, median SB-RFS was 10.9 months with SRT and was not reached with TBRT (HR, 0.48; P = .002).

OS was significantly improved with TBRT (HR, 0.59; p = .032); estimated 24-month survival was 35.7% with SRT vs 61.7% with TBRT. Grade 3 or higher treatment-related adverse events were comparable between the 2, with 19.3% in the SRT group vs 18.1% in the TBRT group.

GammaTile consists of 2×2-centimeter collagen tiles, each embedded with 4 cesium-131 seeds in titanium capsules. Weinberg explained that surgeons "wallpaper" the resection cavity at the time of closure, initiating radiation delivery immediately. Approximately 90% to 95% of the total dose is delivered within 5 weeks, at a total dose that can exceed what stereotactic platforms typically deliver.

How Institutions Can Implement GammaTile

Weinberg noted that centers with existing brachytherapy programs face the lowest adoption barrier. Meanwhile, new programs require a coordinated team consisting of a neurosurgeon to implant tiles, a radiation oncologist to guide placement and treatment planning, and a radiation physicist to manage tile ordering, calibration, storage, disposal, and patient safety education; some centers have radiation oncologists participate remotely.

Approximately 20% of SRT-assigned patients in the ROADS trial did not receive their postoperative radiation, which is consistent with rates seen across prior studies due to neurologic recovery, wound complications, cancer progression, or travel barriers.

TBRT eliminates that failure point. Faster completion of total cranial treatment (median 1 day vs 30 days) also reduces interruptions to systemic therapy, which the investigators suggest may underlie the observed OS benefit.