Tumor treating fields with radiation for glioblastoma: a narrative review

Background and Objective: With a phase 3 clinical trial (EF-32, ClinicalTrials.gov: NCT04471844) currently underway examining the potential benefit of concurrent chemoradiation and tumor treating fields (TTFields) for patients with glioblastoma (GBM), we present the following narrative review to highlight the current evidence that supports this approach. The current management paradigm for GBM includes maximal safe surgical resection followed by concurrent chemoradiation with further temozolomide (TMZ) and TTFields used as maintenance therapy. Despite several treatment advances over the past few decades, the overall prognosis remains poor and new strategies are currently under investigation, including the use of chemoradiation concurrently with TTFields.Methods: In this review, we will discuss the preclinical and clinical work that has been performed combining both TTFields with radiation. We performed a narrative review of peer-reviewed articles related to the management of glioblastoma with regard to concurrent chemoradiation and TTFields and synthesized the data in the context of our clinical experience and practice. PubMed, Medline, Embase, Cochrane Library, and various center-specific guidelines were searched for literature regarding concurrent chemoradiation with TTFields for patients with GBM.Key Content and Findings: Driven by preclinical studies demonstrating the synergy between TTFields and radiation, more recent clinical work has been performed and has shown that combining treatment is both feasible and tolerable.Conclusions: In this review, we will discuss the mechanism of action which TTFields and radiation share, as well as discuss the toxicities of combining therapy in patients with GBM. Based on institutional experiences, we will highlight treatment techniques, including scalp sparing methodology and modified computed tomography (CT) simulation workflow, when concurrent TTFields and radiation are given. Lastly, we will provide discuss management considerations, specifically scalp prophylactic interventions and treatments, when using concurrent TTFields with chemoradiation.