This same protection seems to exist among men who have the liver disease cirrhosis. Men with cirrhosis have a lower incidence of BPH than men with healthy livers, and doctors think it may be because they have higher concentrations of circulating female hormones. If so, you would be trading a single benign disease for two far more serious ones. Finally, the question everyone asks is whether BPH increases your chance of getting prostate cancer. Unfortunately, research has not been able to resolve this issue.
Some studies show increased risk, some show none, and others show a decreased risk.
The best way to summarize the data would be to say that no strong relationship between BPH and cancer has yet to be proved. BPH occurs in the periurethral and transition zones of the prostate, the area of tissue that surrounds the urethra as it passes through the gland. The growth begins within the muscular and fibrous cells of the prostate, later expanding to include the fluid-secreting glandular cells. As the BPH tissue in the transition and periurethral zones grows, the expanding mass pushes against the surrounding tissue in the central and peripheral zones, which can only be moved so far until it compresses against the outer capsule. BPH growth persists even after there is no more room within the prostate, and that is when the increased pressure begins to squeeze the urethra closed and cause symptoms of urinary obstruction.