Hi-good discussion. I use NutritionFacts.org, a non-profit organization that specializes in nutrition- here's what their chatbot answered:
The best available evidence points to a whole food, plant-based diet centered around fruits, vegetables, whole grains, and legumes (chickpeas, lentils, beans, tofu). In a landmark randomized controlled trial, Dr. Dean Ornish and colleagues appeared to slow, stop, and even reverse the progression of early-stage prostate cancer with just such a diet — no chemo, no surgery, no radiation. After one year, the subjects' bloodstreams were nearly eight times better at suppressing the growth of cancer cells, and biopsies showed a downregulation of critical cancer genes.

So what should we eat more of? Tomatoes, broccoli-family vegetables, soy foods, and flax seeds have all been associated with decreased prostate cancer risk. And what should we cut back on? Meat, dairy, eggs, poultry, and refined carbohydrates have all been linked to increased risk. In fact, men with more aggressive cancer who regularly ate chicken and turkey had up to four times the risk of prostate cancer progression — even worse than red meat! Eggs showed a significant twofold increased risk of progression as well.

The good news is, regardless of whether we elect chemo, surgery, or radiation, we can always improve our diets. A prostate-healthy diet is a breast-healthy diet is a heart-healthy diet is a body-healthy diet.

Learn more here: see nutritionfacts.org site and search for these videos-

Reversing Early-Stage Prostate Cancer Progression with a Plant-Based Diet and Lifestyle Program

Treating Advanced Prostate Cancer with Diet: Part 2

Too Much Soy May Neutralize Benefits

Prostate vs. Plants

Carnitine, Choline, Cancer, & Cholesterol: The TMAO Connection

Treating Advanced Prostate Cancer with Diet: Part 1

How Not To Die

How Not To Age