I have always believed that the immune system does destroy most cancers. It’s just that a few get away.
When I was growing up, childhood leukemia was a death sentence. No one survived. Now, well read about it upthread.
The science-fiction editor John Campbell had some quirky ideas (he published L. Ron Hubbard’s Dianetics and appeared to believe in it. But he once suggested the idea a “licensed quack”. They could use any treatment they liked. The one requirement was that they keep complete records. That still doesn’t rise to the level of double-blind tests, but even anecdotal evidence might be enough to justify one. But the real problem is that they would have every incentive to lie. Too bad.
The only difference between “traditional” medicine and “alternative” medicine is an unwillingness on the part of traditional medicine to rely solely on anecdotal approaches.
The most anecdotes can do is trigger a process for a formal investigation. Traditional medicine does not consider some approaches “alternatives” and some approaches “scientific.” Everything that might help gets investigated to some degree; it doesn’t matter if it’s coffee enemas, apricot pits, acupuncture or cyclophosphamide. Obviously some alternative approaches (living in a crystal pyramid, e.g.) get a briefer evaluation than others, but in general every approach is on the table.
The canard that alternative medicine advocates promote is that traditional medicine has a stake in preventing alternative therapies from becoming mainline therapies. That’s just silly. Any physician treating cancer is overwhelmingly anxious to heal, and has an extraordinary incentive to bring to traditional medicine the newest cure.
What is well-recognized in traditional medicine is the limitation of the anecdote, and the need to avoid a post hoc ergo propter hoc fallacy for any given success.