Experimental Evaluation of Tumor Growth Rate Related to Age

The differences of the growth rate of MH 134 tumor inoculated in younger or older mice were experimentally investigated in this study. The age-related tumor growth rate were evaluated as the changes of a tumor size to food pad ratio respectively. In this study, a 6 weeks-old, a 9 weeks-old and a 20 weeks-old C3H/He mice were correctly selected and prepared according to age. From the aspect of age factor in tumorbearing host, MH 134 tumor growth rate as well as survival rate after inoculation of 2.5 x 104, 2.5 x 105 and 2.5 x 106 tumor cells were simulatenously investigated in each age groups. Interestingly enough, a depressed tumor growth rate was noted in older mice in comparison with those in younger mice, whereas survival rates showed almost the same between in younger and older mice groups. While as many as 2.5 x 106 of MH 134 tumor cells were inoculated, the differences in tumor growth rate between younger and older mice were apparently pronounced. The rapid tumor growth in young mice, furthermore, were definitely denoted. Meanwhile, the improvement of survival rate in older mice had not become manifest regardless of slow growth, as compared in the two age group. Age affected some aspect of inhibitory tumor growth, whereas this assumption was not consistent with prolongation of survival time. This results reported here ensured the differences of tumor growth rate in tumorbearing host concerning age. Needless to say, the reliability of tumor resection as a treatment against cancer has been substantiated even for the elderly patients in order to enable survival rate significantly improve