Presenter(s)
J. Janopaul-Naylor1, B. R. Eaton2, L. J. Sudmeier2, H. K. G. Shu2, K. B. Hoang3, E. K. Nduom4, and J. Zhong2; 1Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, 2Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, 3Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 4Emory, Atlanta, GA
Purpose/Objective(s): Tumor Treating Fields (TTF) have shown benefit for supratentorial glioblastomas in the adjuvant and recurrent setting. However, brainstem tumors were excluded from seminal trials due to technical limitations of earlier versions of TTF devices. We performed a pilot study to assess modern TTF targeting of brainstem glioblastomas.
Materials/Methods: A multi-site, single institution, open label pilot study of TTF for pathologically confirmed brainstem gliomas (thalamus, cerebral peduncles, midbrain, pons, and medulla) was conducted from 12/2021 – 1/2025. All patients were prospectively evaluated for quality of life and neurological function at baseline and following treatment. Safety was primary outcome using National Cancer Institute Common Terminology Criteria for Adverse Events assessed. Secondary outcomes included response and overall survival.
Results: Twelve adults were consented and 2 withdrew prior to starting TTF. Median age was 53 years old (range 28-73). Three patients exhibited H3 K27 mutations while the rest were WHO 2021 Grade 4 Gliomas. Median TTF use was 16 hours per day (IQR 11 - 21 hrs) with median duration 3.2 months (IQR 2.5 – 3.9 months) for a cumulative median 1,170 hours of use (IQR 950 – 2,070 hours). After median follow-up 15.1 months (IQR 12.4 - 19.9 months), 1-year overall survival was 74% and median overall survival was not reached. Four patients experienced Grade 2+ toxicity, of which all were attributed unlikely or unrelated to TTF. These included limb edema and pain, anorexia, pneumonia, leukocytosis, thrombocytopenia, and mental health episode. No patients experienced toxicity that was possibly, probably or definitely related to TTF. On neurocognitive assessments (mean + STD) there was minimal change in Mini-Mental Status Exam Scores from baseline (25.0 + 4.1), 2 months (25.6 + STD 4.0), and 4 months (25.3 + 3.7), in Trail Making Test A from baseline (70.0 sec + 25.9), 2 months (112.1 sec + 108.2), and 4 months (83.3 sec + 39.9), or in Trail Making Test B from baseline (246.1 sec + 140.6), 2 months (252.7 sec + 138.5), and 4 months (292.1 sec + 190.7). Patient reported quality of life on FACT-Br was stable from baseline (98.3 + 19.1), 2 months (97.7 + 17.0), and 4 months (96.3 + 22.7).
Conclusion: In the first prospective evaluation of TTF for brainstem gliomas, we showed that treatment was safe and feasible. Although based on a limited sample, our patients also demonstrated promising outcomes, with median survival not reached at greater than 15 months of follow-up. Neurocognitive function and quality of life were similarly promising. This trial suggests that patients with brainstem gliomas should not be excluded from consideration for TTF and likely biologically benefit similarly as supratentorial tumors.