Jennifer Matthews: At 70 years old, Speed Klinzing has outlived all his family members.

Speed Klinzing: My mom died at 56. My dad at 57. My oldest brother at 49. My next oldest brother at 58, and my next one at 67.

Jennifer Matthews: Four of them died of cancer. To avoid that same fate, klinzing is being proactive.

Speed Klinzing: I figured if something should happen, that the man upstairs says it's time to have cancer, then I want to be some place where I can catch it early.

Jennifer Matthews: That place is city of hope where Speed was in study on prostate cancer prevension. There are several treatment for the disease but prevension is another story.

Dr. Timothy Wilson: There are no clear cut options currently for prevension for prostate cancer.

Jennifer Matthews: Dr. Timothy Wilson hopes that the drug finasteride will change that. In smaller doses, it's commonly known as Propecia for baldness. It works by stopping testosterone's conversion to DHT -- a more active form of the hormone.

Dr. Timothy Wilson: We know that prostate cancer is a hormone-dependent cancer. DHT is more active and more potent in prostate cancer development.

Jennifer Matthews: A study of more than 20,000 men showed finasteride decreased prostate cancer risk by 25 percent.

Dr. Timothy Wilson: I think its tremendously significant. I would think that it should be seriously considered in those men at highest risk.

Jennifer Matthews: Speed took the drug for seven years, and so far, so good.

Speed Klinzing: Seventy is not old, and as long as you stay healthy and keep active, that's the whole key.

Jennifer Matthews: Speed is hoping that will keep him one step ahead of cancer. This is Jennifer Matthews reporting.