Targeted drug delivery strategies to treat lung metastasis

Background: Most cancer patients die of metastatic disease, and in a high proportion of cases, from lung metastasis. Methods to target therapy to metastatic disease in general and specifically to lung metastasis are required. Objective: To describe the current and potential tools for the treatment of lung metastasis. Methods: Literature search tools were used with no predefined limitations to encompass the main tumor targeting methods. Methods in standard clinical use, in clinical trials and in preclinical development are reviewed. Data about treatment of lung metastasis and solid tumors are emphasized. Results: Physically targeting therapies to lung metastasis is feasible by aerosol-carried agents, magnetic targeting and intravascular devices. Biological targeting includes methods such as polymers and liposomes, which are based on the principle of enhanced permeability and retention of large molecules in tumor vascular field. Ligand-targeted treatments depend on cancer-specific antibodies or receptors. Few of these methods are in clinical trials or in standard clinical use. However, promising techniques are in advanced preclinical or early clinical studies. The authors believe that targeted treatments will be one the major anticancer tools in the near future.