A Novel Scheme for Optimal Control of a Nonlinear Delay Differential Equations Model to Determine Effective and Optimal Administrating Chemotherapy Agents in Breast Cancer

Background: determining the optimal and effective scheme for administrating the chemotherapy agents in breast cancer is the main goal of this scientific research. the most important issue here is the amount of drug or radiation administrated in chemotherapy and radiotherapy for increasing patient's survival. this is because in these cases, the therapy not only kills the tumor cells, but also kills some of the healthy tissues and causes serious damages. in this paper we investigate optimal drug scheduling effect for breast cancer model which consist of nonlinear ordinary differential time-delay equations. methods: in this paper, a mathematical model of breast cancer tumors is discussed and then optimal control theory is applied to find out the optimal drug adjustment as an input control of system. finally we use sensitivity approach (sa) to solve the optimal control problem. results: the goal of this paper is to determine optimal and effective scheme for administering the chemotherapy agent, so that the tumor is eradicated, while the immune systems remains above a suitable level. simulation results confirm the effectiveness of our proposed procedure. conclusion: in this paper a new scheme is proposed to design a therapy protocol for chemotherapy in breast cancer. in contrast to traditional pulse drug delivery, a continuous process is offered and optimized, according to the optimal control theory for time-delay systems.