Researchers from the University of Connecticut reviewed the progress of 767 men who were aged between 55 and 74 when they were diagnosed with prostate cancer, and discovered that men with low-grade prostate cancer had only a slight risk of dying from the disease, even 20 years after diagnosis. The key seems to be the type of prostate cancer diagnosed. High- or low-grade will pretty much determine your risks, but even men with high-grade cancer still have a life expectancy of 10 years without intervention.