A colon polyp is a small growth that forms on the inner lining of the large intestine. Polyps are common, and most never cause harm. Certain types, however — especially those called adenomas — can slowly change into colon cancer over a period of years.
That slow timeline is actually good news. When polyps are found and removed early, most colon cancers never get the chance to develop. Polyps vary in shape and size: some lie flat against the colon wall, others hang from a small stalk, and a person may have one or several.
Do polyps cause symptoms?
Most polyps cause no symptoms at all, which is exactly why screening matters. Occasionally, a larger polyp bleeds, showing up as visible blood in the stool or as unexplained low iron on a blood test. Rarely, a large polyp can change bowel habits.
Because warning signs are so uncommon, waiting for symptoms is not a dependable strategy. Screening is designed to find polyps while they are silent and simple to remove.
How polyps are found
Colonoscopy is the most thorough test, because it examines the full length of the colon and allows polyps to be removed during the same visit. Stool-based screening tests can detect hidden blood or abnormal DNA, but a positive result still needs to be followed by a colonoscopy. Your gastroenterologist can help you choose the screening approach that fits your history.
How polyps are treated
Nearly all polyps can be removed during a colonoscopy, most often with a thin wire loop passed through the scope. Removal is generally painless and adds little time to the exam. Each polyp is then sent to a laboratory, where a specialist examines it under a microscope and identifies its type.
Those results guide the follow-up plan. Based on the number, size, and type of polyps found, your gastroenterologist will recommend when your next colonoscopy should take place. Keeping that schedule is the most reliable way to keep new polyps from becoming a problem.
When to talk to a gastroenterologist
Most adults should begin discussing colon cancer screening with their care team at age 45, and sooner when polyps or colon cancer run in the family. Whatever your age, make an appointment if you notice rectal bleeding, unexplained anemia or fatigue, or a lasting change in your bowel habits.
Questions about your care?
This page is general education, not personal medical advice. Your care team is happy to talk through what it means for you.