[Optimization of the exposure of normal and transformed cell populations to phase-specific agents]

Dynamic behavior of stem cells population of the "critical" tissue (normal population) and tumor cell population under periodic treatment with a phase-specific cytotoxic agent was considered. The results were used for optimization of anticancer chemotherapy. The schedules of treatment were found which provide a maximum rate of tumor-cell elimination for any given rate of the normal population size decrease. If the mean generation times of normal and tumor populations differ (which was stated for many tumors), usage of the optimal period markedly increases the selectivity of therapy, while application of other periods can result in selective elimination of the normal population. Problems concerned with practical realization of the proposed regimes are discussed.