Nanoparticles! Do they boost cancer treatment?

Actually, Yes they do. Using gold nanoparticles (AuNPs) in conjunction with conventional megavoltage X-rays, researchers at Brigham and Women's Hospital, Dana-Farber Cancer Institute and Harvard Medical School (Boston, MA) are predicting that the tumour vasculature will receive a significant enhancement in local dose. Not only could this dose boost promote vascular shutdown in tumours, the hope is that it will suppress metastases and improve patient outcomes (Int. J. Radiat. Oncol. Biol. Phys. doi: 10.1016/j.ijrobp.2010.10.022).

"Based on the promising results of our theoretical calculations, we believe that the use of AuNPs represents enormous possibilities for improving radiation therapy," assistant professor Ross Berbeco from Harvard's Department of Radiation Oncology told medicalphysicsweb. "Our goal is to develop an agent that can be used clinically in combination with conventional radiotherapy beams to provide an additional boost of destructive energy to an important piece of the tumour architecture."

Targeted therapy

One as yet unanswered question in radiotherapy is the role that tumor vasculature, and in particular endothelial cells, plays in the success of therapy. Over the last few years, nanoparticles have gained much interest as either platforms to carry tumouricidal drugs or as agents themselves for enhancing therapy. In this study, the researchers exploit the fact that nanoparticles preferentially accumulate in the tumour vasculature and are essentially dormant until they are bombarded by an X-ray source.

In the presence of low-energy X-rays of around 100–keV, the AuNPs emit photoelectrons that travel a very short distance before depositing their energy in the nearest endothelial cell. "Others have dismissed the dose enhancement that could be initiated by a 6–MV linac photon energy spectrum," commented Berbeco. "We realised that the dose enhancement is sizable at a short distance from the nanoparticles and that the local radiation boost is actually quite substantial. Our method is a doubly targeted therapy. The nanoparticles target the tumour vasculature while the megavoltage radiation targets the tumour."

Source: Medicalphysicsweb.org