You might be missing the point, then, David.
I haven't seen anything, anywhere, claiming that garlic helps PCa - and I don't need to, and I'm not claiming it does. Nor am I, in the least, suggesting that anyone should forgo actual treatment where appropriate. Having undergone treatment, I'm now on the "did it work" routine of PSA tests. Playing a bit of mind game with the hope of avoiding a recurrence is harmless, and MIGHT actually help, and does not involve choosing hoodoo over an actual medical procedure, as the actual medical procedure at this point is wait and hope it doesn't come back. Perhaps bone mets are started by the tips of vampire fangs ;-)
The real facts and figures are that the placebo effect is real, and significant. Look into some of the research on it. Therefore, if I tell myself that "garlic will help" there are research-backed odds that "it will" or rather, that my body will help itself through as yet not understood means.
Could chose purple M&Ms instead of garlic - it's not the "thing" - it's the mind game that matters.
The mind-blowing aspect is that the mind game can work even if you know full well that you are eating a purple M&M. Haven't tracked down that specific piece in a handy online format, but here are a couple of articles to get you started:rstb.royalsocietypublishing.org/content/366/1572/1905.fullwww.annals.org/content/136/6/471.full