Relationship between tumor growth and cachexia during progressive malignant disease: a new measure of the extent of cachexia, the cachexia index.

The relationship between the dynamics of tumor growth and the development of cachexia in C57b1/6j mice bearing the syngeneic transplantable adenocarcinoma EO 771 has been studied. The tumors grow independently of the inoculum size according to the Gompertzian mode of growth, with a maximum growth rate at a tumor size of about 3 g. As a dynamic measure of the degree of cachexia, the cachexia index "K", i.e. the quotient of the alteration of the carcass weight of the animal divided by the alteration of the tumor weight during the same time interval, is introduced. K is superior to a simple estimation of the alteration of the carcass animal weight because it also considers local weight-reducing effects of the infiltrating tumor growth. With respect to cachexia, three phases of tumor growth can be distinguished; cachexia develops mainly during the 2nd phase, i.e. for tumor sizes between 1.0 to 3.5 g which strongly correlates with the maximum growth rate of the tumor.