Prostate cancer is the most common malignancy diagnosed in North American men (other than skin cancer). One out of every 6 to 7 men will develop the disease during his lifetime. The exact cause of prostate cancer is still unknown; however, a combination of genetic, nutritional and environmental factors appear to play a role in its development. Typically, prostate cancer begins in the outer part of the gland. When confined within the prostate, it is called localized prostate cancer. Prostate cancer may behave in many different ways in different men. It may be relatively slow growing, but it may also be more aggressive in its behavior with a tendency to metastasize or spread to the lymph nodes, bones, or other parts of the body. It is this latter form of prostate cancer that is life threatening.