In this talk, we will present a delayed partial differential equation (PDE) model of solid tumor growth and treatment. The model accounts for cell cycle arrest and cell death induced by chemotherapy, and explicitly includes intracellular signaling pathways relevant to drug action. The model is simplified to a nonlinear, non-autonomous DDE and necessary and sufficient conditions for the global stability of the cancer-free equilibrium derived. We also determine conditions under which the system evolves to periodic solutions. This has clinical implications since it leads to a lower bound for the amount of therapy required to affect a cure. Finally, we will present a clinical application of the model, by applying it to the treatment of ovarian cancers. Two types of drugs are considered - platinum-based chemotherapeutic agents that are the current standard of care for most solid tumors, and small molecule cell death inducers that are currently under development. The model is calibrated versus in vitro experimental results, and is then used to predict optimal doses and administration time scheduling for the treatment of a tumor growing in vivo.