Cancer haunts us: its ability to manifest in seemingly-healthy tissue without any evident provocation; the speed with which it can hit -- and the years over which it can linger; the knowledge that, whatever the trigger, it is ultimately the body turning against itself, going mad at a cellular level. While other diseases have emerged with equally (or more) devastating consequences for their victims, cancer holds a deeply-rooted place in the human imagination. A "cure for cancer" stands alongside "living in space" and "thinking machines" as key symbols for many of what The Future will hold.
That part of the future may well be much closer than any of us had dared hope.
Researchers at Rice University, along with a company called Nanospectra Biosciences, have determined that gold-covered nanoparticles, 20 times smaller than a red blood cell, will quickly pool in tumors when injected into the bloodstream. The nanoshells, when illuminated with a near-infrared laser (which otherwise passes harmlessly through living tissue), will heat up sufficiently to incinerate the tumors completely, in every test.
The report of this research was in Cancer Letters (vol. 209, issue 2) in late June. The full report is only available to subscribers, but the abstract tells the story (albeit with considerable jargon). An excerpt:
The following study examines the feasibility of nanoshell-assisted photo-thermal therapy (NAPT). [...] Polyethylene glycol (PEG) coated nanoshells (~130 nm diameter) with peak optical absorption in the NIR [Near-InfraRed] were intravenously injected and allowed to circulate for 6 h. Tumors were then illuminated with a diode laser (808 nm, 4 W/cm2, 3 min). All such treated tumors abated and treated mice appeared healthy and tumor free >90 days later. [...] This simple, non-invasive procedure shows great promise as a technique for selective photo-thermal tumor ablation.
The researchers on this project were D. Patrick O'Neal, Leon R. Hirsch, Naomi J. Halas, J. Donald Payne, and Jennifer L. West.
The Cancer Letters report wasn't the first time this group showed that the nanoshell + NIR laser combination could kill cancer, but this was the first time they've demonstrated that the nanoshells could be administered into the bloodstream, not requiring a direct injection into the tumor. Previous reports (available online) discuss direct-injection nanoshell-mediated treatment (PDF) and the use of nanoshells as an enabler for tumor detection (PDF). Another article from this group, this time including magnetic resonance guidance of the particles, was published on PubMed late last year; a write-up about that research appeared on the website HealthScout.
To answer the obvious follow-up question, the nanoshells (which, in every test since they were developed in the 1990s, appear completely non-toxic) are eventually ejected from the bloodstream, and do not accumulate over time. Information about how the nanoshells work and how the cancer treatment functions from a tech perspective can be found on the Nanospectra website.
From a WC perspective, perhaps the most exciting part of this development is the relative simplicity of the operation. It's non-invasive, does not require the use of elaborate and expensive equipment (relatively speaking), and given the time involved (6 hours of nanoshell circulation, 3 minutes of laser illumination), can be taken care of in a single-day's visit to a medical technician. The only difficult part will be in the intial identification of tumors, and the nanoshell method appears to have application in that regard, as well. If the treatment works in humans as well as it does in mice (and on human cancer cells in vitro), dealing with cancer could be nearly as simple as getting laser vision correction -- and you can do that in some shopping malls. This is not a medical treatment that would be limited by difficulty and equipment expense to the richest nations.
If it works in people as well as it does in mice, that is, and we won't know for a while. Human trials are not yet scheduled.
The only caveat that comes at me upon reading this is how much heat gets transferred to the surrounding tissues? If the heat transfer beyond the tumor is significant, how will this affect the treatments effectiveness in gonadal and brain cancers?
So far, it looks like it is a treatment among other treatments, not a sufficient solution to the entire problem.
Icewriter suggests worrying about the statistics of non-tumor nanoparticle accumulation...