This could be a very interesting development:
http://protomag.com/articles/sniffing-out-lung-cancer
I follow med news anyway, but this is a bit close to home as I smoked for twenty years pretty heavily (quit in '82 for the second and final time). I figure I'd have some of the signs mentioned, also figure I don't have lung cancer (yet, knock wood, or tinfoil).
The article is a good short read. I take it that Proto is a kind of dispatch from Massachusetts General Hospital folks.
Ask me, if you want to hear how I stopped the cigs..