Yes. Double contrast barium enema xray or ct colonography however if some thing is found on either of the above, you will still need a colonoscopy. If either are negative, there is no guarantee that something wasn't missed due to the prep or performance of those studies. Colonoscopy is the gold standard.
Not really, not yet. A colonoscopy is the best way to look for colon cancer because a doctor can get a very clear picture of the colors, shapes, and textures inside the colon (large intestine). Wherever he sees something suspicious, he can do a biopsy or cut out polyps. A little camera in a capsule isn't controllable and can't do biopsies. A ct scan can't do biopsies and isn't a direct view of the inside surface.