Abstract A008: The effect of body mass index on Tumor Treating Fields (TTFields) intensity distribution in the abdomen: results of a simulation model study
Authors: Naveh Ariel , Shapira Nadav 
Published: September 2024

Introduction: Tumor Treating Fields (TTFields) are electric fields that disrupt processes critical for cancer cell viability and tumor progression. They are generated by a portable medical device and delivered noninvasively to the tumor site via skin-placed arrays. TTFields therapy is approved for the treatment of recurrent and newly diagnosed glioblastoma as well as pleural mesothelioma. Recently, the randomized, pivotal (phase 3) LUNAR study (NCT02973789) demonstrated improved overall survival for TTFields therapy (150 kHz) delivered continuously until progression or intolerable toxicity together with an immune checkpoint inhibitor (ICI) or docetaxel (DTX) vs ICI/DTX alone in patients with metastatic non-small cell lung cancer following progression on or after platinum-based therapy. PANOVA-3 (NCT03377491) is an ongoing pivotal (phase 3), randomized, open-label study evaluating the safety and efficacy of TTFields therapy (150 kHz) together with nab-paclitaxel and gemcitabine for the treatment of patients with unresectable, locally advanced pancreatic adenocarcinoma. The effects of TTFields are dependent on several factors (i.e., intensity, frequency, and distribution) which may be affected by tissue composition/conductivity and array layout. Here, we evaluate guideline TTFields array layouts for TTFields delivery to the abdominal region at therapeutic intensities (∼1 V/cm [amplitude]) using simulation models with varying body mass index (BMI). Methods: Computerized phantom models (Ella, females with BMIs of 22, 26 and 30 kg/m2) were used to simulate the distribution of TTFields. Two different arrays sizes (small [13 disks] and large [20 disks]) were applied to the abdominal region of the models based on abdominal TTFields array layout guidelines. Region of interest (ROIs) included the left and right hypochondriac, left and right lumbar, epigastric, and umbilical regions. Simulations were performed using the Sim4Life platform v6.2.1.4910 (Zurich MedTech, Zurich, Switzerland). Electric field intensity distribution maps were generated for each model, and electric field intensity values across all ROIs in the abdomen were analyzed. Results: Electric field intensities were generally lower in the higher BMI model compared with the lower BMI models (field intensities across all ROIs were 1.60–2.57 V/cm for the 22 kg/m2 BMI model, 1.36–2.13 V/cm in the 26 kg/m2 BMI model and 1.35–1.97 V/cm in the 30 kg/m2 BMI model). However, all BMI models achieved TTFields intensities at therapeutic levels (∼1 V/cm) in all ROIs. Conclusions: Results from this simulation-based study demonstrate the feasibility of delivering TTFields at therapeutic intensities to patients with abdominal tumors regardless of their BMI when using abdominal guideline layouts.

Citation Format: Ariel Naveh, Nadav Shapira. The effect of body mass index on Tumor Treating Fields (TTFields) intensity distribution in the abdomen: results of a simulation model study [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A008.