A highly interesting discussion of this topic in the link below, with the information that at least one human trial will be done this year with a technique using nanobots to try and cure a leukemia patient.
The video embedded in the article is a bit long (18 min.), but even watching the first few minutes of it is very educational. It describes how nanotechnology works in a simple way that even non-technical types like me can understand, and also provides a pretty good quick, understandable course in how nanobots work. Its animation features (nanobots at work) are especially good.
A useful article and video for getting a good, quick understanding of how nanotechnology is being applied in the war against cancer.
www.rawscience.tv/nanobots-fight-cancer-first-human-clinical-trial-in-2015/