Colorectal screening, primarily by colonoscopy, contributed to a steep drop in cancer incidence (Yang et al. 2014).
David Lieberman, M.D., professor and head of gastroenterology and hepatology in the OHSU School of Medicine, begins his term as president of the American Gastroenterological Association this week. Lieberman is perhaps best known for his role in establishing the now widely used colonoscopy screening exam for the early detection of tumors and pre-cancerous lesions.

That leadership path began early in his career at OHSU in the 1980s. “We were performing screening sigmoidoscopies [limited to the lower part of the colon] when a fellow asked the question about how many patients with adenomas were not detected with flex sig,” Lieberman recounts in a profile published in the AGA journal Gastroenterology. Lieberman went on to organize and receive funding for Department of Veterans Affairs Cooperative Study no. 380. Between February 1994 and January 1997, the study recruited more than 3,100 male subjects from 13 VA medical centers across the U.S.
Its high-impact findings were published in 2000 in the New England Journal of Medicine. Colonoscopy screening detected invasive cancers or adenomas with high-grade dysplasia in 2.6 percent of subjects. Most of the tumors were found before the cancer had spread and were candidates for curative treatment. More than half the cases of advanced proximal neoplasia would not have been found with sigmoidoscopy.
Since 2000, colonoscopy has become the most widely used form of screening for colorectal cancer, and it’s made a population-level difference in cancer mortality. One study estimated that colonoscopy use in the year 2005 averted 7,300 to 11,700 colorectal cancer deaths in the U.S., and that twice as many deaths could have been avoided with full, equal access to the screening exam.
The VA study led by Lieberman, together with another on Eli Lilly employees, “had a major impact on the decision to cover screening colonoscopy by Medicare and the inclusion of colonoscopy as an average risk screening option in the guidelines of the American Cancer Society and all the GI societies and, last, by the US Preventive Services Task Force in 2008,” writes Dennis Ahnen, M.D., in the Gastroenterology profile. More than a recitation of accomplishments, the piece includes some charming personal perspectives from Lieberman’s colleagues and family members.
“It wasn’t until I was a teenager that I realized that topics like esophageal reflux and the contents of one’s stool were not, in fact, ‘normal’ as part of a dinner table conversation,” observes his son Myrrh Larsen. “But aside from a distorted sense of dinner table etiquette, my father instilled in us the importance of helping others at every opportunity, of always working hard in the pursuit of truth, and that learning from and teaching others is a lifelong practice.” You can read the full profile at the Gastroenterology website.
Lieberman joined OHSU in 1976 as a house officer. He finished his residency in internal medicine as chief resident in 1979-80, and stayed for his fellowship in gastroenterology. He’s been a member of the OHSU faculty since 1982, and head of the GI Division since 1998.
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Further reading:
Use of Colonoscopy to Screen Asymptomatic Adults for Colorectal Cancer by David A. Lieberman, David G. Weiss, John H. Bond, Dennis J. Ahnen, Harinder Garewal, William V. Harford, Dawn Provenzale, Steve Sontag, Tom Schnell, Theodore E. Durbin, Doug B. Nelson, Steve L. Ewing, et al., for Veterans Affairs Cooperative Study Group 380. NEJM (July 20, 2000)
Colorectal cancer mortality prevented by use and attributable to nonuse of colonoscopy by Christian Stock, Amy B.Knudsen, Iris Lansdorp-Vogelaar, Ulrike Haug, and Hermann Brenner. Gastrointestinal Endoscopy (March 2011)
Estimating the magnitude of colorectal cancers prevented during the era of screening: 1976 to 2009 by Daniel X. Yang, Cary P. Gross, Pamela R. Soulos, and James B. Yu. Cancer (June 2014)
Our New President—David A. Lieberman, MD, AGAF, FACG by Dennis J. Ahnen. Gastroenterology (May 2018)