http://www.cancer.gov/cancertopics/pdq/cam/cannabis/healthprofessional/page4
Also here's the website of a woman who's lived 12 years with metastatic disease (liver, lung), which was diagnosed when she was only 30. She is a cancer prevention food guru: kriscarr.com. She has books, vids, cookbooks you can order at her site.
There are more links at the NIH site and all over the web. Basically the above PROVES CBD is effective in antitumor properties for breast and colon cancers. However, the studies cited were done on animals, not humans, and that's b/c there IS no human cancer/CBD/mmj trial conducted by NIH.

However, there are studies from around the world indicating mmj is effective for some human cancers.
That is by no means to suggest not doing the surgery. The colon/liver surgery I had literally saved my life b/c the colon tumor was obstructing my plumbing and I was really sick. The very experienced surgeon said to me, "You won't last long" without the surgery, and all docs I consulted told me to do it immediately. I'm glad I did!
Bottom line is you need to do all research possible to intelligently discuss the options with your docs. Also,go for 2nd and 3rd opinions from top cancer hospitals (usually located in big cities). Small hospitals/clinics in small cities are not the place to resolve big cancer problems, IMO. I live in a small town but had surgery in a big city hosp. with top surgeons, then did the conventional chemo at my nearby cancer clinic.
I also am on my own organic diet based on Kris Carr's + exercise and supplements. So far I'm 6 mos. past chemo and cancer free. Not breathing easy yet but happy! Good luck