In a study on mice, scientists have discovered a way to effectively kill kidney tumours by injecting man-made, microscopic tubes into tumours and heating them with a quick, 30-second zap of a laser.
Researchers at Wake Forest University say that their finding suggests a potential future cancer treatment for humans.
"When dealing with cancer, survival is the endpoint that you are searching for. It's great if you can get the tumour to shrink, but the gold standard is to make the tumour shrink or disappear and not come back. It appears that we've found a way to do that," said Dr. Suzy Torti, lead investigator for the study.
For the study, the researchers used multi-walled nanotubes (MWCNTs), which contain several nanotubes nested within each other.
The tubes, when non-invasively exposed to laser-generated near-infrared radiation, respond by vibrating, creating heat. If enough heat is conducted, tumour cells near the tubes begin to shrink and die.
In a mouse model, the researchers injected kidney tumours with different quantities of MWCNTs, and exposed the area to a three-watt laser for 30 seconds.
It was found that the mice that received no treatment for their tumours died about 30 days into the study.
Mice that received the nanotubes alone or laser treatment alone survived for a similar length of time, said the researchers.
However, in the mice who received the MWCNTs followed by a 30-second laser treatment, the researchers found that the higher the quantity of nanotubes injected, the longer the mice lived and the less tumor regrowth was seen.
In fact, in the group that received the highest dose of MWCNTs, tumours completely disappeared in 80 percent of the mice.
Many of those mice continued to live tumour-free through the completion of the study, which was about nine months later.
"You can actually watch the tumours shrinking until, one day, they are gone. Not only did the mice survive, but they maintained their weight, didn't have any noticeable behavioural abnormalities and experienced no obvious problems with internal tissues. As far as we can tell, other than a transient burn on the skin that didn't seem to affect the animals and eventually went away, there were no real downsides - that's very encouraging," said Torti.
However, the researchers say that before the treatment can be tested in humans, more studies are need to test the toxicity and safety.
The treatment would need to be tested in larger animals before being tested in human trials, as well.
The study has appeared in the latest issue of Proceedings of the National Academy of Sciences (PNAS).