The problem with cancer is that the only conventional way we can kill it is by killing everything similar to it in the process. In other words you're most likely gonna die either way.
RIP: My uncle.
What they are saying is that cancer is caused by mitochondria basically making the cells immortal, therefor allowing a buildup. The drug simply reboots the malfunctioning mitochondria therefor allowing the cells to die. It has no effect on other cells, as their mitochondria are already functioning.
You aren't really "killing" anything, you are simply curing it.
