A retrospective analysis of concurrent versus sequential chemoradiotherapy with tumor electric field therapy in Chinese high-grade glioma patients

Purpose: The optimal timing of Tumor Treating Fields (TTFields) with concurrent chemoradiotherapy (CRT) in high-grade glioma (HGG) remains unclear. This study compared survival and recurrence patterns between concurrent TTFields with CRT (CC-TTF) and sequential TTFields after CRT (S-TTF) in Chinese HGG patients. Methods: In this multi-center retrospective study, 114 HGG patients (70 CC-TTF, 44 S-TTF) treated between 2018-2023 were analyzed. Progression-free survival (PFS), overall survival (OS), and recurrence patterns were assessed using Kaplan-Meier methods, log-rank tests, and Cox regression. Results: The S-TTF group had a considerably longer median PFS (17.9 vs. 13.2 months, p=0.0175) and improved OS (33.4 vs. 21.6 months, p=0.1355) than the CC-TTF group for isocitrate dehydrogenase(IDH) wild-type patients. Recurrent IDH wild-type patients in the S-TTF group had better PFS (12.62 vs. 8.44 months, p=0.0363) and a longer OS (23.7 vs. 18.0 months, p=0.0666). Higher baseline Karnofsky Performance Status (KPS) scores (HR=0.66, p=0.0001) and longer TTFields duration (HR=0.95, p=0.0177) were found to be favorable prognostic factors for OS. However, delayed TTFields initiation (≥2.22 months post-diagnosis) was associated with increased distant progression (p = 0.0388). The recurrence patterns differed significantly between groups, with the S-TTF group having higher distant metastatic rates (34% vs. 26%). Conclusion: Sequential TTFields after CRT may increase PFS in IDH wild-type HGG patients compared to concurrent TTFields with CRT; however, OS advantages need to be validated. Distant recurrence was more prevalent with delayed TTFields commencement, indicating that timing affects illness development patterns. These findings lend support to future investigations aimed at optimizing TTFields inclusion into HGG therapy procedures.