The paper describes a new approach to the treatment of solid malignant tumors. In this approach the tumors are thermally ablated with minimally invasive microwave balloon catheters, and the cavities created in the tumors by the balloon catheters are filled with anticancer agents that can be forced through the ablated malignant tissues to the margins of the tumors in order to destroy any remaining viable tumor cells. In vivo and in vitro experiments are described that illustrate the ability of microwave balloon ablation catheters to rapidly ablate of large volumes of tissues, to create reservoirs for anticancer agents in the ablated (necrosed) tissues, and to force substances with large molecular weights that are introduced into these reservoirs through the ablated tissues to the margins of the ablation.