Abler, Daniel; Büchler, Philippe (August 2017). Computational Study of the Influence of Biomechanical Forces On the Shape of GBM. In: AAPM Annual Meeting 2017. Denver, CO, USA. Jul 30 - Aug 03 2017.
Purpose: Glioblastoma multiforme (GBM) grows rapidly, infiltrating, compressing and displacing surrounding healthy tissue. Most previous studies focused on modeling GBM invasion dynamics, thereby neglecting its mass-effect. This study investigates the influence of biomechanical forces caused by the growing tumor on its shape.
Methods: A mathematical model was developed to simulate GBM invasion and the mechanical interaction between tumor and healthy tissue. Cell proliferation and invasion was modeled as reaction-diffusion process; a solid-mechanics model of brain tissue was used to represent the mass-effect. Both models are coupled by relating local increase in tumor cell concentration to the generation of isotropic strain in the tissue, and solved using the Finite-Element Method (FEM). The model accounts for multiple brain regions with values for proliferation, isotropic diffusion and mechanical properties derived from literature. Tumors were seeded at multiple locations in FEM models based on the SRI24 human brain atlas. Simulation results for three sets of growth parameters were compared to actual tumors obtained from publicly available GBM datasets.
Results: The temporal evolution of tumor cell concentration was simulated, together with the mechanical impact of tumor growth in terms of displacement and tissue stresses. Parameter choices for different levels of growth and invasiveness were correctly reflected in simulation results. However, statistical evaluation of tumor shape showed simulated tumors to be more symmetric than their real counterparts.
Conclusion: In contrast to most previous study, the present model accounts not only for the tumor‘s growth and invasive characteristics, but also for its mass-effect. The study confirms observations from pure growth-invasion models that tumor shape depends on seed position. It extends their findings by showing that inclusion of tumor mechanics, using isotropic material and diffusion properties, is not sufficient to reproduce asymmetric shapes found in real tumors, thus underlining the importance of tissue anisotropy for GBM simulation.
Funding Support, Disclosures, and Conflict of Interest: This project has received funding from the European Union Seventh Framework Programme for research, technological development and demonstration under grant agreement 600841.
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