here is what i've read, and its interesting. i'm a big fan of snopes and they address the topic head on.
http://www.snopes.com/2015/08/24/cannabis-kil...cer-study/

and the NIH does indicate that its for treating cancer symptoms http://www.cancer.gov/about-cancer/treatment/...nnabis-pdq

but then there are stories like this that seem to offer more promise. http://thefreethoughtproject.com/main-stream-...re-cancer/