 So if you're 50 or older, it's time. Even if it doesn't run in your family, most often, colorectal cancer occurs in people with no family history. And it doesn't always cause symptoms, especially early on. So don't wait for symptoms to get tested. Screening helps prevent the disease by finding precancerous polyps so they can be removed. Remove the polyp, prevent the cancer. Screening also helps find colorectal cancer early when treatment works best.