Visual screening of the colon and rectum can be done with a colonoscopy, the procedure that is considered the gold standard in testing because it allows an abnormal polyp or lesion to be visualized.

But a colonoscopy is more than just a diagnostic exam. It can also provide a therapeutic effect because once the abnormality of the colon or rectum is visualized, a physician may attempt to remove it through the scope.

For example, precancerous polyps can often be removed with a colonoscope. Studies have clearly shown that identifying colon cancer at an early stage — such as a small polyp — is beneficial if the polyp is removed.

And if colon cancer is detected at an early stage — that is, before it has spread outside of the colon — removal of the diseased part of the colon can lead to a full recovery.