A minimally invasive method to eliminate circulating agents from an organism to prevent and treat diseases is disclosed. The method utilizes immunomagnetic methods to concentrate and localize disease-associated agents in a small region of the body. Subsequently, the complexes are removed from the body. Removal of disease-causing or disease-promoting agents (circulating tumor cells, bacteria, viruses and virus-infected cells, certain immune cells) would add a significant new option for intervention of disease progression and supplement other therapeutic options.