Spatial Structure of Tumor Growth: A Simulation Study

Continuing previous studies in which tumor diseases were Interpreted as unstable control loops, an attempt is made to determine the spatial stctur and the time behavior of cell renewal systems. For this purpose a computer model for the two-dimensional cell space was developed, which is described by a set of specifications and growth statements. Selected case studies are then simulated by means of a digital computer (CYBER 76). Regarding the development of this model special emphasis was given to the existence of several cell systems with different mean life spans, growing in competition; the variability of the mean life spans of a cell and of the initial configuration of cell patterns; the description of the cell-to-cell interactions; the perturbations of normal cell growth by tumor cells and their elimination in medicine comparable with an irradiation or a removal by surgery; and the consideration of the loss of tumor cells. There have been systematic studies on the influence of the size of a tumor nucleus and the mean life span of a tumor cell on the tumor growth assuming constant cell loss. Furthermore this computer model enables the simulation of simple basic cases which in reality could hardly or not at all be tested. In the future it seems that it will be possible to partly substitute long and expensive biological experimental test series by simulation with the help of these models.