ABSTRACT
Gompertzian Growth and Fractional Cell Kill In order to understand the response of tumors to chemotherapy and the mechanism of relapse, various theories of tumor growth have been developed. The rate of proliferation of a tumor is thought not to be constant. In the early stages, growth is exponential and the growth fraction, the percentage of cells proliferating, is high. As the tumor enlarges, the growth rate slows and the growth fraction falls. This pattern of growth, known as Gompertzian, dictates the effect of chemotherapy: As the tumor grows, fewer cells remain in cycle and the inherent resistance to chemotherapy increases, making the disease harder to cure ( Fig. 4.2 ).
