Higher-Order Sliding Mode Control for Androgen Deprivation Therapy

Prostate cancer results from enlargement of the prostate gland in the male reproductive system. It results in the leakage of a protein called prostate-specific antigen into the primary bloodstream. Several treatments are available for prostate cancer, with androgen deprivation, or hormone therapy, being one of them. This therapy uses drugs that destroy the hormones that accelerate the growth of cancer cells. Numerous mathematical models exist in the literature that consider cancer dynamics under hormone therapy. However, in most of the studies, the cancer cells develop resistance to the therapy, and therefore, there is a need for proper drug scheduling. To achieve this purpose, four different nonlinear controllers (sliding-mode control, super-twisting, integral sliding mode control, and integral-based super-twisting control) are designed using the hormone therapy model. The objective is to bring down the androgen levels that help in the proliferation of cancer cells. The suppression of androgen hormones reduces prostate cancer cells to zero. The asymptotic stability of the controllers is analysed using the Lyapunov stability criteria. The derived control laws provide researchers with information for accurate drug scheduling. All the results are validated using the MATLAB/SIMULINK platform.