Proportion of necrosis in transplanted murine adenocarcinomas and its relationship to tumor growth.

Percentage of necrosis has been measured in 30 murine adenocarcinoma transplants of known volume. It was found that changes in necrotic proportion during the growth of these particular tumors agree with the concept of a core of necrosis surrounded by a viable shell of constant thickness. This means that viable and necrotic fractions were proportional to the surface area of the tumor, which is consistent with the frequently observed superficial distribution of nutrient-supplying arteries. According to this model a plot of 1n tumor volume versus necrotic fraction is sigmoid and, if tumor growth is directly related to viable fraction, such a plot is not compatible with popular mathematical growth equations. However, the equation of von Bertalanffy gives a reasonable fit to the data here for total tumor growth, suggesting that growth too was proportional to surface area and in accord with a surface-related viable fraction and blood supply. An appropriate physiological explanation is given of necrosis development resulting from a superficial nutrient supply.