Abstract
The proliferation of malignant cells and tumor growth can be studied at various levels and from different viewpoints in the field of tumor biology and oncology. The aim of this paper is to outline how control theory and computer science can pave the way to new approaches to interpreting tumor growth and treatment. The present development is based on the hypothesis that the proliferation of malignant cells may be simulated by an unstable closed-loop control circuit. This type of model only describes the number of cells as a function of time. Therefore, an extended model permitting the study of the spatial structure of tumor growth is chosen. This approach leads to three-dimensional models simulating tumor growth in a vascularized tissue segment and opens the possibility of determining optimized chemotherapeutic tumor-treatment schedules. In the future it may become possible to perform computer simulations of different kinds of tumor treatment prior to clinical therapy.