I second Red_34, a colonoscopy will allow the doctor to take biopsies and to actually see your colon. Thought that was the only way to get a 100% diagnosis. Demand one, nobody will take care of your health as well as you do. Don't worry about having one, it really isn't too bad, the fear is worse than the procedure itself.
My fear when I first went to see my GI was cancer too, but he told me that one symptom of colon cancer is unexplained weight loss, which I did not have. If your doctor suspected cancer, I am sure he/she would have you in for a colonoscopy immediately so I would not worry too much.
Meds: None so far. Garlic works to ease flares. My GI laughed when I told him and said it was just coincidence.
Diet: Regular fresh garlic, Biobest yogurt daily, Omega 3 supplements, very limited junk food, carbs and processed food, low fat diet. Lots of fresh fruit and veggies (limited potatoes).
Added: tumeric and probiotics.