Plasma ctDNA in Patients Undergoing Diagnostic Colonoscopy

When the DNA inside of human cells undergoes certain alterations (mutations), the cells may develop into a cancer. The cancer cells may shed this DNA into the blood stream. This circulating tumor DNA (ctDNA) can be detected by very sensitive, specialized laboratory tests. Measurement of ctDNA has been shown to be useful for following patients with known cancer. It has also been found in the circulation of some patients with early stage cancer. The purpose of this study is to examine blood specimens for the presence of ctDNA in individuals without known cancer who are scheduled to undergo a screening or diagnostic colonoscopy in order to see if the ctDNA test can detect a cancer or precancerous condition at a very early stage before the patient becomes symptomatic. The results of this study should help define the role of ctDNA in the detection of early stage colon cancer and to define how sensitive it is (i.e. how well it picks up cancer when it is present) and how specific it is (i.e. how often is ctDNA found in patients with benign diseases or no abnormalities).