Delivering nanomedicine to solid tumors

Nanotechnology offers great promise for the detection, prevention and treatment of cancer. Current limitations of this technology include the heterogeneous distribution of nanoparticles to tumors, caused in part by the physiological barriers presented by the abnormal tumor vasculature and interstitial matrix. This Review discusses these barriers and summarizes strategies that have been developed to overcome them. It additionally examines design considerations for the optimization of delivery of nanoparticles to tumors. Recent advances in nanotechnology have offered new hope for cancer detection, prevention, and treatment. While the enhanced permeability and retention effect has served as a key rationale for using nanoparticles to treat solid tumors, it does not enable uniform delivery of these particles to all regions of tumors in sufficient quantities. This heterogeneous distribution of therapeutics is a result of physiological barriers presented by the abnormal tumor vasculature and interstitial matrix. These barriers are likely to be responsible for the modest survival benefit offered by many FDA-approved nanotherapeutics and must be overcome for the promise of nanomedicine in patients to be realized. Here, we review these barriers to the delivery of cancer therapeutics and summarize strategies that have been developed to overcome these barriers. Finally, we discuss design considerations for optimizing the delivery of nanoparticles to tumors.