In short, primum non nocere - "first do no harm" - and there will be woo associated with cancer treatment. Keep in mind: twenty years ago cannabis was woo. Not all woo is completely inert. Some of it will react badly to the medicines you're taking. All of it will work better if the patient believes in it. So the person in charge of your health regimen? Better know your entire health regimen and if you're going to be scornful and derisive about the choices your patient makes you're going to be in charge of part of their health. The size of your participation is inversely proportional to the size of your scorn.

Wanna know how to kick a kid out of medical care completely? Deride and scorn his parents when they get dodgy about vaccines. Put up a fight, wrap yourself in self-righteous dudgeon and that kid won't see a doctor until they're eighteen at least. The "skeptical" universe really likes to beat people up for their stupidity and malfeasance so they can play madder-than-thou without spending any time on the core problem: distrust of the medical industry. In my experience, this is because they view the medical industry the way nuns view the Pope.

And they are the only ones.