Colonoscopy

A colonoscopy is a procedure that uses a long, flexible tube with a camera (colonoscope) to examine the entire colon and rectum. It is the gold standard for colorectal cancer screening. Over 15 million colonoscopies are performed annually in the US.

Colonoscopy is recommended for colorectal cancer screening starting at age 45 (USPSTF guidelines), surveillance of polyps, evaluation of symptoms like rectal bleeding, chronic diarrhea, unexplained abdominal pain, or iron deficiency anemia, and monitoring inflammatory bowel disease.

Bowel preparation is critical: a clear liquid diet the day before and a prescribed laxative solution to empty the colon. Stop iron supplements, blood thinners, and certain medications as directed. Arrange a driver for after the procedure.

Under sedation (moderate or deep), the colonoscope is inserted through the rectum and advanced through the colon. The doctor examines the lining and can remove polyps (polypectomy) or take biopsies during the procedure. It takes 30-60 minutes.

You rest for 30-60 minutes as sedation wears off. Mild bloating and cramping are normal. Resume eating within a few hours. Take the rest of the day off. Most people return to normal activities the next day.

Risks are low: perforation (0.01-0.1%), bleeding from polyp removal (1-2%, usually minor), adverse reaction to sedation, and rarely, post-polypectomy syndrome. Serious complications are rare.

Alternatives for screening include fecal immunochemical test (FIT) annually, Cologuard stool DNA test every 3 years, CT colonography (virtual colonoscopy) every 5 years, and flexible sigmoidoscopy every 5-10 years. However, any positive result on these tests requires a follow-up colonoscopy.

Screening colonoscopies are covered at 100% (no cost-sharing) under the ACA for average-risk adults starting at age 45. Diagnostic colonoscopies (for symptoms) may have cost-sharing. Medicare covers screening colonoscopy every 10 years.