A colonoscopy is a medical procedure during which a doctor inserts a long, thin tube into a person's rectum and colon. The tube has a light and a camera on the end, so the doctor can see the inside of the person's colon. During a colonoscopy, the doctor may also remove any growths or polyps that they see. Ablation is a medical term that means to destroy. So, during a colonoscopy with ablation, the doctor will use the endoscope to destroy any large growths that they see in the person's colon.