Local control remains a challenge in the treatment of recurrent glioblastomas. Our prior experience indicates that adjunctive cesium-131 brachytherapy, followed by systemic therapy, is a promising option. Here, we extend the initial findings through a multi-institutional study. Clinical information was collected for consecutive, recurrent glioblastoma (isocitrate dehydrogenase wild-type) patients treated at seven participating institutions. All patients underwent systemic treatment after surgical resection/cesium implant. Median progression-free and overall survival (mPFS and mOS) were calculated from the time of cesium tile implantation. The study cohort comprised 43 male and 17 female subjects, with a median of 1 prior glioblastoma recurrence. The mean pre-operative Karnofsky Performance Score (KPS) was 80 (± 15.7). There was one case (2%) of postoperative hemorrhage, one case (2%) of wound breakdown, and one case (2%) of radiation necrosis. The median hospital stay was 2 days (IQR: 2, 4 days). Ten patients in the cohort (16.7%) required 30-day readmission. With a median follow-up of 400 days, the actuarial local control at one year was 88.6% and 79% for MGMT-methylated and -unmethylated patients, respectively (p = 0.17). MGMT-methylated patients showed improved OS (mOS = 487 days (16.2 months)) relative to unmethylated patients (mOS = 244 days (8.1 months), p < 0.001). Notably, patients with postoperative KPS decline showed reduced OS relative to those with stable/improved KPS (mOS of 420 vs. 218 days, respectively, p = 0.008). Patients who adopted the ketogenic diet showed improved OS relative to those who did not (mOS of 451 vs. 239 days, respectively, p = 0.01). There was no statistically significant association between tumor recurrence or prior bevacizumab use and outcomes. This multi‑institutional experience provides evidence supporting the continued development of cesium tile therapy as a treatment option for recurrent glioblastoma.
Chuck et al. (Wed,) studied this question.