You've been hearing a lot about new cancer therapies that deliver drugs directly to tumors, instead of flooding the body with drugs that do a lot of peripheral damage. How do these new therapies work, and how effective are they?
The first thing to note is that therapies that target individual cancer cells are still being worked out in the lab.
For example, one team of scientists at MIT and the University of California, San Diego are experimenting with microscopic bits of magnetic iron oxide that seek out tumors inside the body and mark them. This makes it easier for doctors to detect even the smallest tumors on MRI scans.
What's even more interesting is that the iron oxide particles tend to clump together inside the blood vessels that feed tumors. When enough particles congregate inside the vessels they can clog them, acting as artificial blood clots. Deprive a tumor of blood and nutrients long enough, and it will wither and die.
As for how well this treatment works, that remains to be seen.
At the moment, the research team has tested the particles on mice with cancer. So far they've managed to block about 20% of the blood vessels feeding tumors in mice, which is not quite enough to kill the tumors. With further testing, though, this new therapy may one day soon deal a real blow to tumors not only in mice, but in humans.