Home > Cancer > Colonoscopy and Colorectal Cancer Risk Reduction Get the Flash Player to see this player. Rate: (Click the stars to rate) Published on Dec 17, 2008 by IMReport, Views: 4827 Colonoscopy Significantly Reduces Death from Left-sided Colon Cancer but Not from Right-sided Colon Cancer. Physicians Should Advise Patients of Test Limitations. Colonoscopy looks at the colon using a colonoscope, and a biospy of the colon can be done at the same time. If you have any new stool abnormalities, such as blood in the stool, you should call your doctor to get screened.