There's loads of information on the internet about how lifestyle, diet, and other non-medical interventions can help in cancer ..
Trouble is, much of it is fiction, some of it is a scam to part you from your money, and only a small bit of it is true .. and even a smaller bit proven to be true.
And what's worse, is that it's virtually impossible to separate the good stuff from the snake oil.
My rule of thumb is that if it doesn't cost a lot, and doesn't have side effects, it may be worth thinking about. But I won't spend, or accept ill effects on the off-chance of some possible future benefit.
We live in an age of science; we should KNOW if these things are helpful. And if these things haven't been tested, it's often because the scammers know they won't pass.