TAN YUANSHUN, YANG HUAN
During the process of androgen deprivation therapy for prostate cancer (PCa), stochastic effects in the tumor microenvironment can cause treatment to fall short of the desired effect on tumor clearance. In this paper, the Lévy noise is introduced to describe the random changes of tumor cell number, and a system of stochastic differential equations (SDEs) driven by Lévy noise is established and analyzed. Firstly, through appropriate Lyapunov functions and the solution formula of SDEs driven by Lévy noise, the existence and uniqueness of the global positive solution are proved. Then, employing the theories and methods of stochastic dynamical systems, such as Lévy-Itô's formula, the comparison theorem of SDEs driven by Lévy noise, the exponential martingale inequality and the Borel-Cantelli lemma, the stochastic dynamics of extinction, non-persistence in the mean, weak persistence in the mean and stochastic permanence of PCa cells are studied. Finally, numerical simulation further verifies the theoretical results. Combined with theoretical analysis and numerical simulation, it can be found that the higher the intensity of Lévy noise, the easier the PCa cells are removed.