OPTIMAL DRUG SCHEDULING OF CANCER-CHEMOTHERAPY BY DIRECT SEARCH OPTIMIZATION

An optimal drug delivery policy for cancer chemotherapy is determined by direct search optimization based on random numbers and region contr action, so that the size of a cancerous tumour is minimized at the end of a given time interval. Due to the large number of state constraint s and the threshold function in the state equation, direct search opti mization appears to be most appropriate. However, because of the high dimensionality, a sequence of computer runs was necessary to establish the optimal control policy. The results from a previous run were used to establish the conditions for the following run. The results were t hus improved from one run to the next until the global optimal control policy was established. The results obtained are significantly better than have been previously reported for this problem, and show the dif ficulties that may be encountered in the optimization of high-dimensio nal nonlinear systems.