I'll watch the documentary posted, but I do have to acknowledge my bias in not really buying into the Vitamin B17 cure from what amount I have seen. While I don't agree with anyone getting 20 years imprisonment for selling a holistic medicine, nor do I inherently disagree with holistic cures in general, I agree with EndDaFed that the research doesn't seem to support the claims.
For me, the most damning thing about the claim is that "cancer" is a really broad disease to claim to cure. It's not like saying a medication cures AIDS, which is a specific viral illness. It's more like saying a certain medication cures viral infection. Different cancers come about in different ways, via different mechanisms. Does Vitamin B17 work against small cell lung cancer? Lymphomas? Leukemias? Melanomas? Adenocarcinoma of the colon? Squamous cell cancer of the esophagus? They aren't the same disease, and anyone that suggests they are all due to the same underlying deficiency... I'm sorry, but it simply isn't so.
While it's certainly important to question the sponsors of particular articles, just saying "IT'S ON A GOVERNMENT WEBSITE" isn't really enough to debunk the study. Having been a part of labs with government grants, I can attest that the actual influence of government bodies is nil. Grants represent more a form of government spending waste than they do any insidious influence. As a result, the motives of a researcher to have the personal glory of discovering the "cure to cancer" is far stronger than the researcher concealing the cure to maintain the profits of the business. Researchers tend to be much less big-picture than that. Again, that's just my own personal experience. Take it for what you will.
Ultimately, if you think you're doing the right thing with Vitamin B17, keep on taking it. If it actually does work out for you, all the better. If it doesn't work out and you need the cancer resected, I'll be there to help you out. If you waited too long and the cancer is inoperable, at least you tried what you felt would have saved your life.