TTFields

TTFields, or tumor treating fields, are a cancer treatment modality that uses low-intensity, intermediate-frequency alternating electric fields to disrupt cell division in solid tumors. The fields are delivered noninvasively through transducer arrays placed on the body surface over the tumor. For glioblastoma, arrays are positioned on the shaved scalp and deliver fields typically around 200 kHz, with field intensities of about 1 to 3 V/cm. The proposed mechanism involves interference with mitotic spindle formation and cytokinesis, leading to mitotic arrest and cell death in dividing tumor cells while largely sparing nondividing normal tissue.

Implementation and regulation: Therapy requires a portable device carried by the patient, with arrays worn for most of the day (commonly around 18 hours). Treatment is usually used in combination with standard anticancer therapies, such as temozolomide for glioblastoma. TTFields have received regulatory approvals in several jurisdictions for glioblastoma (both recurrent and newly diagnosed) and for malignant pleural mesothelioma, where adjunctive chemotherapy is used. Use outside approved indications is generally considered investigational and requires careful clinical justification.

Efficacy and safety: Clinical trials have reported improvements in progression-free and overall survival when TTFields are added to standard therapy for glioblastoma, with activity observed in other tumor types in early-phase studies. The most common adverse effects are localized skin reactions under the transducer arrays; other adverse events are typically mild. Limitations include the burden of wearing the device for extended periods and cosmetic considerations, as well as the need for further data on effectiveness across additional cancers.