Effect of tumor size on drug delivery to lung tumors

Drug delivery to solid tumors can be expressed physically using biomechanical phenomena such as convection, diffusion of drug in extracellular matrices, and drug extravasation from microvessels. Applying computational methods to solve governing conservation equations clarifies the mechanisms of drug delivery from the injection site to a solid tumor. In this study, multiple tumor geometries were obtained from PET/CT images. An advanced numerical method was used to solve fluid flow and solute transport equations simultaneously to investigate the effect of tumor size on drug delivery to lung tumors. Data from 20 patients with lung tumors were analyzed and the tumor geometrical information including size, shape, and aspect ratios were classified. In order to investigate effect of tumor size, tumors with similar shapes but different sizes ranging from 1 to 28.6 cm
³
were selected and analyzed. A hypothetical tumor, similar to one of the analyzed tumors but scaled to reduce its size to 0.2 cm
³
, was also analyzed. An ideal bolus injection was considered for the model. The effects of two transport mechanisms, namely convection and diffusion, were considered in this study. The results show because of size of considered lung tumor, the diffusion transport rate is higher than convection transport rate. Based on governing equations, the diffusion transport is only depended on concentration gradient and independent of size of tumor, therefore the predicted concentration profile for considered tumors are similar. When size of tumor is decreased significantly, the drug concentration is also significantly increased.