Tumor treating fields: a new frontier in cancer therapy

Tumor treating fields (TTFields) is a noninvasive, regional antimitotic treatment modality that has been approved for the treatment of recurrent glioblastoma by the U.S. FDA and has a CE mark in Europe. TTFields therapy delivers low-intensity (1-3 V/cm), intermediate-frequency (100-300 kHz), alternating electric fields to the tumor using transducer arrays placed on the skin around the region of the body containing the tumor. TTFields therapy affects metaphase, by disrupting mitotic spindle formation, and anaphase, by dielectrophoretic dislocation of intracellular constituents, resulting in apoptosis. TTFields therapy is frequency tuned to specific cancer cell types. The antimitotic effect of TTFields therapy has been demonstrated in multiple cell lines when the appropriate frequency was utilized. A phase III trial of TTFields monotherapy compared to active chemotherapy in recurrent glioblastoma patients established that TTFields therapy is associated with minimal toxicity, better quality of life, and comparable efficacy to chemotherapy. Ongoing and future trials will evaluate TTFields in newly diagnosed glioblastoma, solid tumor brain metastases, nonsmall cell lung cancer, and ovarian and pancreatic cancers.