The temporal and spatial evolution of the targeting agent within the tumor will be modelled by a continuum approach. The tumor is assumed to be a porous medium composed of cell surface subcompartments, interstitial pore fluids and the vascular compartment. The mass balance equations for the injected agent involve diffusive and convective fluxes through the vascular compartment, across the microvascular wall and through the interstitial compartment. The adsorption and the reaction of the therapeutic agent within the tumor tissue and also the influences of the lymph have to be considered and implemented into the equations. Further, the deformations of the surrounding healthy tissue by the growing tumor will be described by a linear elastic approach. The system of partial differential equations is numerical integrated with a Multiple Interacting Continua (MINC) approach. The flow of the therapeutic agent in the blood vessels, in the healthy tissue and the tumor tissue is each described by one single continuum.