Transcription: Sigmoidoscopy, an examination of the rectum and lower colon with a hollow lighted tube called a sigmoidoscope. It is used to detect colon polyps and cancer, to find the cause of bleeding, and to evaluate other bowel diseases. A newer instrument using fiber optics, the flexible sigmoidoscope, permits easier, safer, and more extensive examination, also called a proctoscopy. See also colonoscopy.