Hyperthermia effects on macroscopic fluid transport in tumors

Combining the effects of transvascular and interstitial fluid movement with the structural mechanics of a tissue is important to accurately describe processes such as nutrient transport in a tumor cell. Further, hyperthermia can have a role; for example, temperature variations can be induced in order to treat some kinds of tumors, like liver tumor. Recently, the study of the effects of hyperthermia on fluid flow and mass transport in biological systems by considering the fluid-structure interaction has gained researchers attention. In the present paper, fluid flow in a tumor mass is analyzed at a macroscopic scale by considering the effects of both solid tissue deformation and hyperthermia. Governing equations are averaged over a Representative Elementary Volume (REV) of the living tissue, and written by means of the thermo-poroelasticity theory. Darcy's law is used to describe fluid flow through the interstitial space, while transvascular transport is described with a generalized Starling's law. The effects of hyperthermia on the living tissue are included with a source term in the tissue momentum equation that considers the thermal expansion. Governing equations with the appropriate boundary conditions are solved with the finite commercial code COMSOL Multiphysics in steady state regime. The numerical model is validated with analytical results from Netti et al. [1997] for an isothermal case. Results are presented in terms of pressure, velocity and temperature fields, for various thermal loads and it is analyzed the effect of hyperthermia on various physical parameters.