Fig. 1
From: Different ODE models of tumor growth can deliver similar results
Schematic representation of the Simeoni tumor growth model. The tumor resides in compartment Z1, with growth described by a tumor growth function. c(t) denotes the plasma concentration of an anticancer agent if present. The drug elicits its effect decreasing the tumor growth rate by a factor proportional to c(t)*Z1(t) through the constant parameter k1. Tumor cells cycle successively through transit compartments Z2, Z3, Z4 before cell death. k2 is a first-order rate constant of transit. The number of transit compartments is arbitrary. The system of ordinary differential equations describing this model is given in the text