Cancer is defined as a group of diseases that happen when cells grow out of control. These abnormal cells can form tumors and spread to other areas of the body. The risk of developing cancer increases as you age due to the natural process of cell turnover. This process happens more rapidly in youth, which is one reason that most cancers are diagnosed in adults. Most of the time, the cause of cell turnover is random DNA errors that happen during replication. These errors can be prevented by a healthy diet, physical exercise, and stress reduction. Not all cell turnover is bad; in fact, most of the cells in your body are replaced every 14 days. The rate of cell turnover decreases with age, which is why most cancers are diagnosed in adults. Unfortunately, there is no way to stop this process entirely, though you can reduce your risk by avoiding things that cause DNA damage.