A group of health experts wants adults to start getting tested for colon cancer at age 45. That is five years younger than the age it formerly recommended for colon cancer screenings. Screening is a medical term. It means the act of doing a test on a person to look for evidence of a disease or health problem. In the United States, colon cancer rates have been falling in recent years. But the recent screening proposal, released by the U.S. Preventive Services Task Force, shows that experts are concerned about rising colon cancer rates in people under the age of 50.