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VA research in action

Colonoscopy for colorectal cancer screening

December 28, 2021


©Getty Images/Elena KHarchenko

One of VA’s important research objectives concerning the treatment of cancer is improving doctors’ ability to diagnose colorectal, or colon, cancer, a disease that affects about 150,000 Americans every year. Colorectal cancer can be cured if diagnosed early, yet one-third of all patients who develop the cancer will die from the disease. VA diagnoses 4,000 cases of colon cancer every year among its Veteran patients.

In 2000, VA researchers at 13 medical centers throughout the nation published a study (VA Cooperative Study 380) in which they reviewed two types of screenings for the cancer (colonoscopies and sigmoidoscopies) to determine their relative effectiveness. They found that colonoscopies, in which a long, flexible tubular instrument is used to visually inspect the entire colon, could detect abnormal growths called neoplasms better than sigmoidoscopies, which use a flexible instrument that inspects only the lower colon.

The study was one of the first large trials to show that screening colonoscopy was safe and feasible for patients without symptoms, and that this method could often detect lesions missed by sigmoidoscopy. According to a 2018 article in the journal Gastroenterology, the study helped drive Medicare’s 2001 decision to cover screening colonoscopy. The VA study was also a major factor in the recommendation of colonoscopy as a screening option for average-risk patients in clinical guidelines that would come from the American Cancer Society and other organizations.

The team used colonoscopy to examine the entire colon’s lining in 3,121 apparently healthy people aged 50 to 75, and found about 10% had colon cancer or serious precancerous groups. They also found at least a third of the lesions colonoscopy found would have been missed by sigmoidoscopy.  

Principal investigator: Dr. David A. Lieberman, VA Portland Health Care System

Selected publications:

Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380. Lieberman DA, Weiss DG, Bond JH, Ahnen DJ, Garewal H, Chejfec G. N Engl J Med. 2000 Jul 20;343(3):162-8.

VA diagnoses 4,000 cases of colon cancer each year, VA VAntage Point blog, Mar. 21, 2019

Our New President—David A. Lieberman, MD, AGAF, FACG - Gastroenterology (

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