Experience about Chemoradiation treatment with or without Concurrent Tumor-Treating Fields (TTFields) in Newly Diagnosed Glioblastoma (GBM) Patients in China

Abstract Background:Tumor-Treating Fields (TTFields) and radiotherapy may have synergistic anti-glioma effect based on preclinical study. Chemoradiation concurrent with TTFields has become a hot topic in clinicians. This study provided preliminary experience about the clinical outcomes of patients with newly diagnosed Glioblastoma (GBM) received concurrent and adjuvant TTFields with chemoradiation or adjuvant TTFields only based on a cohort of patients treated at Huashan Hospital, China. Methods: This is a retrospective study analyzing clinical outcomes for newly diagnosed GBM patients treated at Huashan Hospital who received TTFields treatment. Patients were divided into two groups: one group received TTFields adjuvantly after the completion of chemoradiation (referred to as the A-TTF group), and another group received TTFields concurrently with chemoradiation and continued TTFields after treatment completion (referred to as the CA-TTF group). Treatment efficacy and toxicities were assessed and compared between the two groups. Overall survival (OS) and progression-free survival (PFS) were evaluated using the Kaplan-Meier method. To account for confounding factors, the Cox proportional hazards regression model, data matched by propensity score, and inverse probability of treatment weighting (IPTW) based on the propensity score were used for effectiveness evaluation. Results: A total of 72 patients with ndGBM were included in the study, 41 received concurrent and adjuvant TTFields in combination with chemoradiotherapy (concurrent and adjuvant TTFields group, CA-TTF), and 31 received adjuvant TTFields with temozolomide (adjuvant TTFields group, A-TTF). Skin toxicity was common but tolerated, there was no significant difference between the CA-TTF and A-TTF groups. The two groups were well balanced in age, sex, extent of resection, MGMT methylation status, KPS, as well as compliance and duration of TTFields usage. The TERT promoter mutation rate was 63.4% in the CA-TTF group versus 41.9% in the A-TTF group. With a median follow up of 18.0 months, there was no significant difference in PFS between CA-TTF and A-TTF groups (14.2 and 15.0 months, respectively, p=0.92); or the median OS (20.8 and 20.0 months, respectively, p=0.92). After IPTW, there remained no significant differences in PFS or OS, but the adjusted hazard ratio (HR) for PFS decreased from 0.93 (95% CI: 0.53-1.63, p=0.82) to 0.77 (95% CI: 0.44-1.30, p=0.344), and the adjusted HR for OS decreased from 0.96 (95% CI: 0.52-1.79, p=0.91) to 0.74 (95% CI: 0.40-1.37, p=0.336) for OS. Conclusions: Concurrent chemoradiation and TTFields treatment is safe for ndGBM patients. No survival difference was presented between CA-TTF and A-TTF groups in this series of patients, but a potential advantage for those undergoing concurrent TTFields treatment. This hypothesis need validation through large-scale clinical trials.