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

Abstract

Abstract Background:The TTFields have received the FDA approval as adjuvant therapy after completing radiotherapy in patients with newly diagnosed glioblastoma (GBM). TTFields and radiotherapy may have synergistic anti-glioma effect based on preclinical study. This study evaluated clinical outcomes of patients with newly diagnosed 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 of patients with newly diagnosed GBM (ndGBM) received TTFields treatment at a single institution from 2020-2021. TTFields treatment was either given adjuvant after chemoradiation alone or concurrent and adjuvant with chemoradiation treatment. Treatment outcome and toxicities were evaluated and compared between the two groups. Overall survival (OS) and progression-free survival (PFS) were evaluated with Kaplan- Meier method. The Cox proportional hazards regression model, data matched by propensity score, and inverse probability of treatment weighting (IPTW) based on propensity score were used to evaluate the effect of TTFields and account for confounding factors. 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). 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. With a median follow up of 17.95 months, there was no significant difference in PFS between CA-TTF and A-TTF groups (14.2 and 15.0 months, respectively, HR: 0.97, p=0.92); or the median OS (20.8 and 20.0 months, respectively, HR: 0.97, p=0.92). After IPTW, there remained no significant differences in PFS or OS. In the STR/biopsy subgroup, the CA-TTF group showed an improving trend in terms of both OS and PFS compared to the A-TTF group, but due to small sample size it is not conclusive. Conclusions: In this pilot study, no survival difference was detected in ndGBM patients between CA-TTF and A-TTF groups. However, CA-TTF group may have worse prognosis than A-TTF group due to the inclusion of early progression patients. The benefit of concurrent TTF with chemoradiation is currently being tested in a phase 3 trial.