KLK3 and prostate intraepithelial neoplasia: Men in the intervention group had smaller tumours, reduced involvement of surgical margins and/or extra‐prostatic tissues with cancer (73% vs. 18%, organ‐confined disease) and less diffuse involvement of the prostate by high‐grade prostatic intraepithelial neoplasia (33% vs. 0%, focal involvement) in comparison with those in the control group. Mean plasma PSA levels were lower in the intervention group compared with the control group.