Critical diffusion ranges for oxygen and glucose in tumor tissue considering Michaelis-Menten kinetics.

The supply conditions for O2 and glucose in tumor tissue distinctly deteriorate with increasing tumor mass. As a result retardation in growth, lysis and necrosis take place because critical diffusion ranges are partially surpassed in heavier tumors. Applying in vivo-data to a special analogue computer it is possible to investigate the supply conditions including the range of very low O2 tensions and glucose concentrations. Using a definite arrangement of blood vessels it can be shown that the supply conditions only for one of the limiting substrates, i.e. for O2, are better than assumed hitherto. However, even the more realistic model reveals that regional failure in glucose and O2 obligatorily occurs during tumor cell proliferation.