After I got PCa, I studied and studied all about the supplements and how diet co Puld be a beneficial factor in keeping PCa at bay. This included a study of flax, tomatoes, broccoli, etc.
The only fairly good evidence I found with a couple of beginning scientific studies, had to do with the benefit of ingesting pomegranate juice... 8 ounces per day. According to the studies, pure pomegranate juice slowed the growth of or killed cancer cells in mice and slowed the growth in humans. The scientific community is continuing to study the effect.
I drink 8oz on occasion. I try to drink it each day, but I sometimes forget. I buy it at Costco to same some $.
Flax and flax oil seemed to have some risks associated with it. Ingesting soy for fighting PCa has been debunked. Ingesting tomatoes for fighting PCa has been debunked. However, there have been recent studies showing a benefit ingesting broccoli.
I think there are a lot of double-blind studies that need to occur before I would solely rely on one of these "remedies."
My 2 cents worth,