Regarding the link above which was incorrect, here is a correct link, not to pubmed, but to another site that published the trial abstract...
clincancerres.aacrjournals.org/content/12/13/4018I decided to send an email to the MD that ran the study, seeking more info, asking about
other studies, etc. I did this in consideration of the fact that the study was run in 2006.
I got a response today, which follows:
"The only large clinical trial that is published was by Carducci et al, published one or two years ago. We have completed a randomized study that we hope to have published shortly. I still have a handful of patients on our original study for over 10 years with stable but elevated PSAs. My overall impression is that there are genetic variations that lead to greater or lesser benefits from taking anti-oxidants"
Here is a link to, I believe, the study he referred to in his response.
www.ncbi.nlm.nih.gov/pubmed/23985577