Even when a colonoscopy is completely “normal,” colorectal cancer can still develop later. It’s uncommon, but it happens — we call these interval cancers. And they don’t occur because colonoscopy isn’t effective. It’s still one of the most powerful tools we have. They happen because real biological and technical challenges exist: • Some polyps hide in places that are simply hard to visualize. • Flat lesions can blend into the lining of the colon. • Certain tumors grow faster than expected betwee