Abstract 3208: Optimal array layouts for tumor treating fields therapy in glioblastoma: Oblique array layouts are superior to standard LR and AP positions

Abstract

Abstract Introduction: Tumor treating fields (TTFields) is a new and effective treatment for glioblastoma. Two pairs of transducer arrays are placed on the scalp of the patient to deliver low intensity, alternating electric fields, which inhibit mitosis and cancer growth. In the present study, we investigated systematic variations in electrode array positions to identify optimal layouts, which induce the highest electric fields in the tumor tissue. Method: The electric field distribution was calculated using finite element methods applied to a realistic computational head model. Array positions were rotated systematically in fifteen-degree intervals around a central cranio-caudal axis of the head to obtain thirteen different layouts in the same plane. Tumors were introduced in the computational mesh at nineteen different fronto-parietal positions in the same plane as defined by the electrode positions. Results: Electrode array layout greatly affected the field distribution. For the vast majority of tumors, two optimal and oblique array orientations were identified. At these positions, field intensities were approximately 30-40% higher compared to the standard anterior/posterior and left/right positions. In addition, the two optimal layouts were oriented at ninety-degree interval to each other. Correspondingly, a single optimum layout was identified when analyzing the combination of two pairs of arrays. Each tumor position was associated with only one optimum (combined) layout, which was generally oblique relative to the sagittal plane (15-45 degrees). An oblique layout at forty-five degrees to the sagittal plane was effective for most tumor positions and in all cases it was superior to the default layout combination of anterior-posterior and left-right positions. Conclusion: Our results provide guiding principles for optimal electrode placement, which will be helpful, especially in situations where the placement must be changed due to concurring clinical conditions such as shunts, scars, tissue rash etc. Patient specific models should be for more accurate TTF distributions. Additional research is needed to confirm these current results. Citation Format: Nikola Mikic, Anders Korshøj. Optimal array layouts for tumor treating fields therapy in glioblastoma: Oblique array layouts are superior to standard LR and AP positions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3208.