Without a doubt, if you have cnacer of ANY KIND, do not use X-factor... or any other anabolic for that matter. Anabolics cause growth which of course includes cancer cells if they happen to be present.
Arachidonic acid does not cause prostate cancer. I read a study a while back that compared various fatty acids and how they affect prostate cancer development. AA was a zero risk factor. But Linoleic acid--such as that found in flax seed--appeared to increase the risk of prostate cancer.
Just food for thought.