Objective  To evaluate preliminary safety and effectiveness of a tumor electric field treatment system in patients with recurrent glioblastoma.

  Methods  In total, six patients were enrolled from April 2020 to August 2020 in Xiangya Hospital and Chinese PLA General Hospital. The median age was 53 (48-68) years. Patients with recurrent glioblastoma were enrolled, and their clinical data were collected. The safety and effectiveness of the treatment system were evaluated by assessing the incidence of adverse events, time to progression (TTP), and overall survival (OS).

  Results  In total, the median follow-up time was 10.9 (8.4-22.7) months. Progressive disease was observed in all patients, five patients were followed up to death, and one patient is still alive. The median time to tumor progression (mTTP) was 4.7 months (95% CI: 3.62-5.78), median progression-free survival (mPFS) was 4.7 months (95% CI: 3.62-5.78), and median OS was 10.9 months (95% CI: 8.86-12.94). The objective response rate (CR+PR) was 33.3%; the disease control rate (SD+PR+CR) was 83.3%. The most common treatment-related adverse event was scalp rash, with an incidence rate of 66.7%, which could be effectively relieved by adjusting the sticking position of the transducer arrays, keeping the wound dry, and applying steroid or antibiotic ointment.

  Conclusions  This study showed the preliminary safety and effectiveness of tumor electric field therapy in patients with recurrent glioblastoma.