  Stochastic resonance induced by external factor is considering to investigate
the complex dynamics of tumor. The surrounding environment and the treatment
effects on the tumor growth are considered as additive and multiplicative
noises in growth model. The adaptability of tumor to treatment is presented by
correlation of these two noises. The Fokker-Plank equation is deduced to study
the probability distribution function and mean number of tumor cells in
different conditions. The mean number of tumor cells can be controlled by the
correlation and intensity of noises.
