Does Screening Help People Live Longer?
Finding some cancers at an early stage (before symptoms appear) may help decrease the chance of dying from those cancers. For many cancers, the chance of recovery depends on the stage (the amount or spread of cancer in the body) of the cancer when it was diagnosed. Cancers that are diagnosed at earlier stages are often easier to treat or cure. Studies of cancer screening compare the death rate of people screened for a certain cancer with the death rate from that cancer in people who were not screened. Some screening tests have been shown to be helpful both in finding cancers early and in decreasing the chance of dying from those cancers. Other tests are used because they have been shown to find a certain type of cancer in some people before symptoms appear, but they have not been proven to decrease the risk of dying from that cancer. If a cancer is fast-growing and spreads quickly, finding it early may not help the person survive the cancer. Screening studies are done to see whether de
