Here's the basic problem with your premise: There are many, many cancer researchers in various universities and hospitals who would all LOVE to come up with a new treatment, let alone a cure. These people are not on the payroll of the AMA, ACS, or the drug companies; they are just individual researchers (and groups of researchers) who all want to advance their own careers by discovering new cancer treatments, regardless of what effect it might have on drug companies etc. These people have no discernible motivation to "demonize" anything that might work.
In fact, the more surprising or outlandish the new treatment, the more they wish it would work, because a surprising new treatment that doesn't seem like it should work would bring a lot more fame and research papers and grants than an "unsurprising" new treatment. So, while it is perhaps true that researchers in some big drug company that made a lot of money treating cancer would have a motivation to suppress or ignore "alternative" treatments that they couldn't make money off of, there are still many serious cancer researchers who do not have such a motivation.