Screening tests play a key role in detecting polyps before they become cancerous. These tests can also help find colorectal cancer in its early stages, when you have a good chance of recovery.
Screening methods include:
- Colonoscopy, the most sensitive test for colorectal polyps and cancer. If polyps are found, your doctor may remove them immediately or take tissue samples (biopsies) for analysis.
- Virtual colonoscopy (CT colonography), a minimally invasive test that uses a CT scan to view your colon. Virtual colonoscopy requires the same bowel preparation as a colonoscopy. If a polyp is found, you'll need a colonoscopy to have it removed.
- Flexible sigmoidoscopy, in which a slender, lighted tube is inserted in your rectum to examine it and the last third of your colon (sigmoid) and rectum. If a polyp is found, you'll need a colonoscopy to have it removed.
- Stool-based tests. This type of test works by checking for the presence of blood in the stool or assessing your stool DNA. If your stool test is positive you will need a colonoscopy.
Your doctor is likely to remove all polyps discovered during a bowel examination. The options for removal include:
- Removal with forceps or a wire loop (polypectomy). If a polyp is larger than 0.4 inches (about 1 centimeter), a liquid may be injected under it to lift and isolate the polyp from surrounding tissue so that it can be removed.
- Minimally invasive surgery. Polyps that are too large or that can't be removed safely during screening are usually removed laparoscopically, which is performed by inserting an instrument called a laparoscope into the bowel.
- Colon and rectum removal. If you have a rare inherited syndrome, such as FAP, you may need surgery to remove your colon and rectum (total proctocolectomy).
Some types of colon polyp are far likelier to become malignant than are others. But a doctor who specializes in analyzing tissue samples (pathologist) usually must examine polyp tissue under a microscope to determine whether it's potentially cancerous.
If you have had an adenomatous polyp or a serrated polyp, you are at increased risk of colon cancer. The level of risk depends on the size, number and characteristics of the adenomatous polyps that were removed.
You'll need follow-up screenings for polyps. Your doctor is likely to recommend a colonoscopy:
- In five to 10 years if you had only one or two small adenomas
- In three years if you had more than two adenomas, adenomas measuring 0.4 inches (about 1 centimeter) or larger, or certain adenomas
- Within three years if you had more than 10 adenomas
- Within six months if you had a very large adenoma or an adenoma that had to be removed in pieces
It's important to fully prepare your colon before a colonoscopy. If stool remains in the colon and obstructs your doctor's view of the colon wall, you will likely need a follow-up colonoscopy sooner than the guidelines specify.
Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this disease.
Preparing for your appointment
You may be referred to a doctor who specializes in digestive diseases (gastroenterologist).
What you can do
- Be aware of any pre-appointment restrictions, such as not eating solid food on the day before your appointment.
- Write down your symptoms, including any that may seem unrelated to the reason why you scheduled the appointment.
- Make a list of all your medications, vitamins and supplements.
- Write down your key medical information, including other conditions.
- Write down key personal information, including any recent changes or stressors in your life.
- Ask a relative or friend to accompany you to help you remember what the doctor says.
- Write down questions to ask your doctor.
Questions to ask your doctor
- What's the most likely cause of my symptoms?
- What kinds of tests do I need? Do these tests require any special preparation?
- What treatments are available?
- What are the chances these polyps are malignant?
- Is it possible that I have a genetic condition leading to colon polyps?
- What kind of follow-up testing do I need?
- Should I remove or add any foods to my diet?
- I have other health conditions. How can I best manage these conditions together?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask other questions during your appointment.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may leave time to go over points you want to spend more time on. You may be asked:
- When did you first begin experiencing symptoms, and how severe are they?
- Have your symptoms been continuous or occasional?
- Have you or has anyone in your family had colon cancer or colon polyps?
- Has anyone in your family had other cancers of the digestive tract, the uterus, ovaries or the bladder?
- How much do you smoke and drink?
Colon polyps care at Mayo Clinic
Aug. 18, 2017
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- Colon polyps. National Institute of Diabetes and Digestive and Kidney Disease. https://www.niddk.nih.gov/health-information/digestive-diseases/colon-polyps. Accessed March 18, 2017.
- Colon polyps. American College of Gastroenterology. http://patients.gi.org/topics/colon-polyps/. Accessed March 18, 2017.
- Polyps of the colon and rectum. American Society of Colon and Rectal Surgeons. https://www.fascrs.org/patients/disease-condition/polyps-colon-and-rectum. Accessed March 18, 2017.
- Colorectal cancer: Screening. Rockville, Md.: U.S. Preventive Services Task Force. https://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/colorectal-cancer-screening. Accessed April 5, 2017.
- Feldman M, et al. Colonic polyps and polyposis syndromes. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. 10th ed. Philadelphia, Pa.: Saunders Elsevier; 2016. https://www.clinicalkey.com. Accessed March 18, 2017.
- Niederhuber JE, et al., eds. Colorectal cancer. In: Abeloff's Clinical Oncology. 5th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2014. https://www.clinicalkey.com. Accessed March 18, 2017.
- Goldman L, et al., eds. Neoplasms of the small and large intestine. In: Goldman- Cecil Medicine. 25th ed. Philadelphia, Pa.: Saunders Elsevier; 2016. https://www.clinicalkey.com. Accessed March 18, 2017.
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- Brown A. Allscripts EPSi. Mayo Clinic, Rochester, Minn. Jan. 25, 2017.
- Rajan E (expert opinion). Mayo Clinic, Rochester, Minn. April 10, 2017.
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