I think this was one of the articles referenced in the discussion above: Flaxseed supplementation (not dietary fat restriction) reduces prostate cancer proliferation rates in men presurgery
The full-text article is free through PubMed cebp.aacrjournals.org/content/17/12/3577.long
The discussion is interesting reading - it considerably softens the headline claim:
"...further studies are needed before we can definitively support flaxseed supplementation as a proven complementary therapy for prostate cancer. To date, however, the evidence suggests that flaxseed (a) is a good, low-cost source of select vitamins and minerals and fiber, (b) is well-accepted and safe to use, and (c) warrants further testing as a preventive or complementary therapy for prostate cancer. "
For the type/amount of supplementation used, see Randomization and Implementations section.
Hmm! The more I reads, the confuseder I gets.