One of the more difficult aspects of colorectal cancer detection is that, in many cases, the cancers or polyps do not initially cause any symptoms. The goal is to recognize the potential for disease as early as possible, in order to facilitate prevention or cure. That’s why screening is so significant; it identifies whether an asymptomatic person has a disease or condition that might lead to cancer. Surveillance, on the other hand, involves testing those with a history of colorectal cancer, or who have been identified as being at a higher risk for developing it.