Association of Tumor Treating Fields (TTFields) with survival in newly diagnosed glioblastoma: A systematic review and meta-analysis

Abstract Background: Tumor Treating Fields (TTFields) became an FDA-approved treatment option for patients with newly diagnosed GBM in 2015 on the basis of the randomized controlled EF-14 trial. Subsequent approvals worldwide and increased adoption of TTFields has led to the question of whether or not a consistent survival benefit has been observed in the real world setting, and whether device usage has played a role. Methods: We conducted a literature search using PubMed, Embase, and Google Scholar to identify clinical studies evaluating overall survival in adult patients with GBM treated with TTFields. Comparative studies and single-cohort studies reporting on survival outcomes were included in the analysis. Inter-study heterogeneity was assessed using the Cochran Q test and quantified using the Higgins I2 statistic. Results: Of 7 studies evaluating the clinical efficacy of TTFields in newly diagnosed patients, 5 studies (reporting on a total of 1,228 patients) compared the addition of TTFields to standard of care (SoC) vs SoC alone, and were included in a pooled analysis for overall survival. Meta-analysis of comparative studies indicated a significant improvement in overall survival for patients treated with TTFields vs those not receiving treatment. Inter-study heterogeneity was examined, and a sensitivity analysis indicated the pooled effect was robust and not dependent on any individual study. Furthermore, among studies reporting data on TTFields device usage, an average device usage rate of 75% or higher was found to consistently associate with prolonged survival when compared to an average usage rate below 75% (P = 0.001). Conclusions: Pooled analysis of comparative TTFields studies suggests survival may be improved with the addition of TTFields to standard chemoradiotherapy treatment for patients with newly diagnosed GBM, and that a 75% usage rate may be meaningful in the real-world setting. Citation Format: Patrick Conlon, Gitit Lavy-Shahaf, Noa Urman, Matthew T. Ballo. Association of Tumor Treating Fields (TTFields) with survival in newly diagnosed glioblastoma: A systematic review and meta-analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3213.