Abstract 4450: Novel transducer array layouts to optimize the treatment of multiple brain metastases with tumor treating fields

Introduction: Tumor Treating Fields (TTFields) is an antimitotic cancer treatment approved for the treatment of Glioblastoma Multiforme (GBM). TTFields are delivered using 2 pairs of transducer arrays positioned on the shaved scalp of the GBM patient to optimize the TTFields dose delivered to the tumor. This results in an increased dose of TTFields to the affected tumor region, whilst reducing the intensity of the fields to other regions. Brain metastases, or secondary brain tumors, occur in 10 to 30 percent of adults with cancer. Cancer types most likely to cause brain metastases are lung, breast, colon, kidney and melanoma. When using TTFields to treat brain metastases, it may be desirable to deliver TTFields at therapeutic intensities to the entire brain, in order to treat multiple rather than a single lesion. We investigated novel transducer array layouts designed to deliver a uniform distribution of TTFields to the entire brain. Methods Computer simulations were used to calculate the field distributions generated by different array layouts. The simulations utilized a realistic computerized head model of a 40+ years old human male prepared in-house from a T1 MRI series. Using Sim4Life v3.0 (ZMT Zurich), we simulated the delivery of TTFields using pairs of array layouts placed at different locations on the head and neck. To analyze the field distributions, the brain was divided into five regions: (1) the cerebellum, brain stem and other infra-tentorial anatomical regions; and (2-5) the four quadrants of the cerebrum. The mean and median field intensities in the five regions generated by each layout were calculated and compared. Results Median intensities between 1.5 V/cm to 1.7 V/cm within all regions were achieved using a layout in which one pair of arrays was placed on the right temple and left scapula, while the second pair was placed on the left temple and right scapula. This layout yielded a uniform intensity distribution within the brain. Conclusion We have identified a novel TTFields array layout that could potentially be used to treat the entire brain with sufficiently high intensity to treat for brain metastases. The ongoing Phase 3 METIS study [NCT02831959 is investigating radiosurgery with TTFields for 1-10 brain metastases from non-small cell lung cancer. Citation Format: Ofir Yesharim, Ariel Naveh, Ze9ev Bomzon. Novel transducer array layouts to optimize the treatment of multiple brain metastases with tumor treating fields [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4450.