From the introduction: The ultimate role of mathematical modelling in cancer chemotherapy is to provide a basis for chemotherapy regimes and to make qualitative predictions about the dynamic evolution of the disease based on the eytokinetic parameters of the tumor/patient and the drug parametric configuration. Models for cancer chemotherapy can be deterministic or stochastic and at the same time can be cell cycle specific or nonspecific. Here, we consider a cell cycle independent model, which may be found in [M. Eisen, Mathematical models in cell biology and cancer chemotherapy. Lecture Notes in Biomathematics. 30. Berlin etc.: Springer (1979; Zbl 0414.92005); G. W. Swan, “Tumor growth models and cancer chemotherapy”, in: J. R. Thompson (ed.) and B. W. Brown (ed.), Cancer modeling. New York, NY: Marcel Dekker. 91–179 (1987); T. E. Wheldon, Mathematical models in cancer research. Bristol, etc.: Adam Hilger (1988; Zbl 0696.92002)].