gms | German Medical Science

Objective: Over the past decade, tumour treating fields (TTF) has moved from novel to established part of the therapeutic armamentarium for high-grade glioma. As of 2020, the Joint Federal Committee (G-BA) broadly approved the use of TTF in newly diagnosed glioblastoma (GBM). However, there is a wide range of further applications of TTF that still need to be explored and validated in clinical trials. This study aims to give an overview of published research and ongoing trials in this field.

Methods: Data regarding published studies, clinical trials and grants was obtained through the meta-research platform Dimensions, which harvests data from sources such as CrossRef, PubMed, the Directory of Open Access Journals, Open Citation Data, clinical trial registries, patent offices, and over 100 publishers. The search terms [(“tumor treating fields” OR “tumour treating fields” OR Optune OR NovoTAL) AND (glioblastoma OR GBM OR astrocytoma OR oligodendroglioms OR oligoastrocytoma)] was used.

Results: Since 2009, 482 studies on TTF in glioma have been published. The number of publications increased exponentially until 2019 when 140 studies were published and decreased in 2020 with 67 studies published by the end of November. The most common journals were Neuro-Oncology (IF 10.9; n=167), Journal of Clinical Oncology (IF 32.9; n=26) and International Journal of Radiation Biology (IF 2.3; n=23). 173 of the publications originated from the USA, followed by Germany (n=37) and Israel (n=22). In total, 51 clinical trials on TTF in glioma were identified, 14 of which are completed and 37 ongoing. 13 of these trials were phase 1, 24 were phase 2, 11 were phase 3, and 3 were phase 4. 28/37 ongoing trials are being conducted in the USA. Ongoing trials mainly evaluate the effect of TTF on newly diagnosed or recurrent GBM in combination with a variety of radiotherapy, chemotherapy and immunotherapy approaches. Another topic of interest appears to be the role of radiographic imaging in glioma treatment with TTF. 39 completed studies and 10 ongoing studies have been funded, most commonly by the American National Cancer Institute (n=20). 35 of the ongoing clinical trials are sponsored by Novocure.

Conclusion: There is rapidly growing research interest in TTF in glioma treatment, mainly for GBM. Ongoing clinical trials also appear to focus on this subcategory of gliomas. Most of the research appears to be conducted in the USA, where most of the research funding is provided.