Nanotechnology in the treatment of cancer

Background: Chemotherapy can induce severe side effects in patients due to nonselective activity towards healthy cells during the treatment of cancer. This can lead to an alteration of the dosage regimen and in some cases to premature cancelation of chemotherapy, which reduces its therapeutic effect and prolongs the treatment period. Adverse side effects can also influence the patient's quality of life during and after the treatment. Inclusion of anti-tumour drugs in nanocarrier systems can reduce the adverse side effects by passive and/or active targeting of tumour cells. Conclusions: Nanocarrier systems achieve passive targeting of tumours through enhanced permeability and retention effect (EPR effect), which is mainly the result of leakiness of tumour vasculature. Furthermore, active targeting of tumour cells can be achieved through the conjugation of targeting ligands to the surface of nanoparticles, which selectively bind antigens or receptors overexpressed on the surface of tumour cells. In this way, the interaction between healthy tissue and anti-tumour drugs is reduced. Consequently, anti-tumour drugs formulated in nanocarriers have less side-effects and are safer in comparison with a free drug, thus enabling higher doses and better efficay of anti-tumour therapy. To date, European Medicines Agency (EMEA) and Food and Drug Administration (FDA) have approved nine nanocarrier-based medicines for the treatment of cancer. The safety of nanoparticles is yet to be fully explored. However, their toxicity is known to be enhanced with reactive oxygen species, which are associated with inflammation.