Cancer is a disease in which cells show an atypical behavior and begin to divide abnormally without control. Furthermore, these cells can spread to other tissues and result in the development of new tumors. It is very difficult to find a treatment that discriminates between tumor cells and healthy cells because cancerous cells are from the person who has the disease and they are not an external and foreign pathogen easily recognizable by the immune system. Thus, the treatments that currently exist for cancer disease are quite nonspecific and they also attack healthy cells, producing a highly specific toxicity and, therefore, severe side effects.
Moreover, drugs used in cancer treatment are metabolized and eliminated rapidly from the body, the administration of large amounts of drugs necessarily leading to the increase of the unspecific toxicity produced by the drug.
Nanotechnology may provide the solution to these problems by the synthesis of nanoplatforms that are able to make these drugs more specific for tumoral tissues, thus increasing the drug half-life in the body and thereby reducing non-specific toxicity and thus the side effects of the drugs. Some of the strategies employed in the field of nanotechnology against cancer to improve anti-tumor therapy are, for example, overcome by the MDR phenotype, which has some tumor cells (thanks to different materials used in the synthesis of nanoparticles), active targeting against tumor cells (because of its union with different structures that recognize tumor cells) or make the nanoparticles sensitive to certain conditions that allow the release of the drug transported to the tumor site (for example conditions of acidity or alkalinity of the environment). For these reasons, nanotechnology applied to the biomedical sciences has been having a great development in recent years.
In this chapter, we review the different therapeutic strategies in the fight against cancer in which nanotechnology can help, describing the materials most widely used in tumor therapy, presenting a great versatility thanks to which nanomedical platforms can be used to overcome the current limitations in the use of free antitumor drugs.