I've read a half dozen studies about sugar and cancer and while there is anecdotal evidence that sugar could contribute to getting cancer, I've not found any study that says that sugar causes or prevents cancer grown once you have it - at least not done on a large enough scale to be considered definitive.
I talked to three oncologists and asked them specifically about this and their answer was the same: while there are studies, nothing has been proven to an extent as to be medically relied upon.
I'm sure there are other opinions and studies, but the ones I've read that have some implication were done with very small subsets of men and showed negligible changes that could exclude other circumstances that may have arrived at the same conclusion.
So, like all things in the medical field this could be true or it could be untrue and no matter what we do there will always be a differing opinion on the matter. You see this even on this forum where people can point to article after article of a miracle treatment that they went with and are good, but why aren't all doctors providing the miracle treatment then?
I don't discount anyone's experience, if it worked then it worked and thank God - but I have to rely on educated professionals in the medical industry that tell me what should be done and while they may be wrong I have to give considerable weight to their medical opinion. It's very easy to go down numerous rabbit holes for all kinds of treatment options.
I choose not to believe that doctors are just so greedy that they want to recommend surgery just to line their pockets, to the exclusion of better methods that might save patients.
In the end we have to rely on what feels right for us - this is where my research led me so I have to rely on that and not constantly feel like I'm second guessing everything lest I go insane. But, to reiterate: I do NOT judge anyone for their beliefs/treatments/opinions on the topic, this is a terrible disease and there are many paths.
I do not think it is greed, it may be trust. I opted for a HIFU procedure to eliminate just the small Gleason 7 tumor on one side of my prostate, leaving some Gleason 6 on the other side. I needed approval to get the procedure, and the main issue is whether I would do all the follow-up? I also had an infection from the biopsy, so elected not to do another biopsy after the procedure, but will need more frequent MRIs if I do not do biopsies. They want us to live, and if they do not think we will follow up, the best procedure for someone not likely to follow up is removing the prostate.