Douglas K. Rex, MD, FASGE




Douglas K. Rex, MD, FASGE is Distinguished Professor of Medicine at Indiana University School of Medicine, Chancellor’s Professor at Indiana University Purdue University Indianapolis, and Director of Endoscopy at Indiana University Hospital in Indianapolis. He co-authored the colorectal cancer screening recommendations of the American College of Gastroenterology (ACG) and the U.S. Multi-Society Task Force on Colorectal Cancer. He also authored the recommendations on quality in colonoscopy of the U.S. Multi-Society Task Force on Colorectal Cancer and the ACG/American Society for Gastrointestinal Endoscopy (ASGE). He has authored more than 200 original research papers, 55 book chapters, 200 invited papers, 40 editorials, and 40 guideline papers. He is the current chair of the U.S. Multi-Society Task Force on Colorectal Cancer. He served in the ACG as Chairman of the Board of Governors and is a Past President of the ACG. He is a member of the Governing Board of ASGE and a recipient of the Rudolph V. Schindler Award from ASGE.



Aries Pharmaceutical

Boston Scientific



Research Support

Boston Scientific



EndoAid Ltd.






  • Colon

    If the Attending’s ADR Is Low, Fellows Can Help

    Douglas K. Rex, MD, FASGE reviewing Tziatzios G, et al. Dig Liver Dis 2019 July 2.

    A number of studies have found that a second observer, including fellow participation in the procedure, can improve colonoscopy adenoma detection rate. In this study, researchers reviewed 19 studies evaluating the effect of fellow involvement in colonoscopy to determine the impact of fellow involvement on detection rate.

  • Colon

    Eat More Fish to Prevent Colon Cancer

    Douglas K. Rex, MD, FASGE reviewing Aglago EK, et al. Clin Gastroenterol Hepatol 2019 June 25.

    Fish intake was estimated from questionnaires given to 521,324 persons, of whom 6291 developed colorectal cancer. N-3 long chain-polyunsaturated fatty acids, which are found primarily in fish, were measured in the plasma of 461 cancer cases and 461 matched controls to determine the association with colorectal cancer risk.

  • Colon

    NBI Tops LCI in Head-to-Head Match-Up

    Douglas K. Rex, MD, FASGE reviewing Leung WK, et al. Gastrointest Endosc 2019 July 2.

    There has been enthusiasm for linked-color imaging, which emphasizes red color and has a substantially different appearance than narrow-band imaging and blue-light imaging. Investigators compared narrow-band imaging with linked-color imaging in a randomized tandem study performed in 272 patients.

  • Colon

    Correct Pathology Reading of Serrated Lesions Deemed of Limited Importance

    Douglas K. Rex, MD, FASGE reviewing Bleijenberg A, et al. Endoscopy 2019 June 13.

    In a post-hoc simulation study of patients undergoing colonoscopy, guidelines from the U.S. Multi-Society Task Force on Colorectal Cancer and the European Society of Gastrointestinal Endoscopy were applied to see how much variation in surveillance intervals they produced based on pathologic interpretation of serrated-class lesion subtypes.

  • Colon

    First Clinical Study of Artificial Intelligence for Detection at Colonoscopy: It Works

    Douglas K. Rex, MD, FASGE reviewing Wang P, et al. Gut 2019 Feb 27.

    Artificial intelligence shows great promise for improving polyp detection and prediction of histology during colonoscopy. A randomized trial with 1058 patients compared results of a deep learning-based artificial intelligence program assisting polyp detection versus standard colonoscopy.

  • Colon

    Fellows Have High Incidence of Musculoskeletal Injuries; Ergonomic Training Helps

    Douglas K. Rex, MD, FASGE reviewing Villa E, et al. Endosc Int Open 2019 June.

    Nearly half of GI fellows surveyed reported 1 or more musculoskeletal injuries that appeared endoscopy-related. This study compared the risk of injury for fellows who received ergonomic training to those who did not.

  • Colon

    Those Vessels You See After EMR: Should You Burn Them?

    Douglas K. Rex, MD, FASGE reviewing Lee HS, et al. Gastrointest Endosc 2019 June 5.

    During colorectal EMR, blood vessels are often seen in the base of the defects after resection, and endoscopists wonder whether these vessels are the cause of subsequent bleeding. A new randomized trial examined whether cauterizing these exposed vessels would reduce bleeding.

  • Colon

    Cancer Recurrence and Cancer-Specific Mortality Risks After T1 Cancer Endoscopic Resection

    Douglas K. Rex, MD, FASGE reviewing Antonelli G, et al. Gastrointest Endosc 2019 June 5.

    Previous meta-analyses of studies on T1 cancer resection were often based on surgical removal of lesions. This meta-analysis includes studies that evaluated endoscopic removal of low- and high-risk T1 cancers and is informative for discussions with patients about the risk of cancer after endoscopic resection of T1 lesions.

  • Colon

    Should Surveillance Intervals Be Different for 6 to 9 mm Versus 1 to 5 mm Adenomas?

    Douglas K. Rex, MD, FASGE reviewing Anderson JC, et al. Gastrointest Endosc 2019 May 21.

    Comparing small and diminutive adenomas, this study evaluated whether the size of adenomas removed at baseline colonoscopy increased the risk of advanced adenomas at follow-up.

  • Colon

    Cuff Versus Cap Ends in Draw

    Douglas K. Rex, MD, FASGE reviewing Sola-Vera J, et al. Endoscopy 2019 May 16.

    Researchers conducted a study that included 711 patients with symptoms, surveillance indications, or positive fecal blood tests to compare the effectiveness of Endocuff-assisted versus cap-assisted colonoscopy at detecting polyps.

  • Colon

    Prevalence and Associations of Traditional Serrated Adenoma

    Douglas K. Rex, MD, FASGE reviewing Kim J, et al. Gastrointest Endosc 2019 May 4.

    Traditional serrated adenoma (TSA) is a rare type of lesion that is uniformly dysplastic. To determine the prevalence, risk factors, and characteristics of TSA compared to sessile serrated polyp and conventional adenoma, investigators evaluated nearly 32,000 medical records of patients who had been screened for colonoscopy.

  • Colon

    Current Status of Hot Versus Cold Snare Polypectomy for 4-10 mm Polyps

    Douglas K. Rex, MD, FASGE reviewing Jegadeesan R, et al. Endosc Int Open 2019 May.

    Expert advice for resection of flat and sessile 4-10 mm colorectal polyps is progressively moving toward cold snare resection without submucosal injection and including a margin of normal tissue. This study examined the evidence supporting cold snare resection of 4-10 mm colorectal polyps.

  • Colon

    Chromoendoscopy Found Ineffective in Largest Study of Lynch Patients

    Douglas K. Rex, MD, FASGE reviewing Haanstra JF, et al. Gastrointest Endosc 2019 Apr 24.

    Chromoendoscopy is sometimes advocated in Lynch syndrome, but data on the effectiveness of chromoendoscopy for neoplasia improvement in Lynch syndrome have been mixed. In a multicenter trial, 246 Lynch patients were randomized to white-light colonoscopy or colonoscopy with chromoendoscopy in the proximal colon to determine the effectiveness of chromoendoscopy at detecting neoplasia.

  • Colon

    Monitor Size Did Not Affect ADRs

    Douglas K. Rex, MD, FASGE reviewing Jovani M, et al. Gastrointest Endosc 2019 Apr 12.

    A single-center trial randomly assigned 15 endoscopists to perform colonoscopy in a room with a 32-inch versus 19-inch diagonal monitor to determine if a larger monitor size would improve adenoma detection rates.

  • Colon

    On Second Thought, NBI Actually Does Improve Detection

    Douglas K. Rex, MD, FASGE reviewing Atkinson NSS, et al. Gastroenterology 2019 Apr 15.

    The widely held conclusion regarding narrow-band imaging (NBI) is that it improves diagnosis but not detection. In a meta-analysis using patient-level data from 4491 patients in 11 trials, researchers compared adenoma detection rates in NBI to white-light endoscopy.

  • Colon

    AI Accurately Predicted Deep Submucosal Invasion

    Douglas K. Rex, MD, FASGE reviewing Lui TKL, et al. Endosc Int Open 2019 Apr.

    Artificial intelligence (AI) programs have accurately differentiated adenomas from serrated class lesions in previous reports. This is a report of a deep-learning AI program using endoscopic images of large colonic lesions to determine the accuracy of AI at predicting whether curative resection was possible.

  • Colon

    Three-Day Low-Residue Diet Did Not Improve Bowel Preps Over 1-Day Diet

    Douglas K. Rex, MD, FASGE reviewing Gimeno-Garcia AZ, et al. Endoscopy 2019 Apr 3.

    A low-residue diet for part or all of the day prior to colonoscopy has not reduced the quality of bowel preparation in previous studies. This new study evaluated whether a 3-day low-residue diet improved bowel cleansing quality compared to the same diet for 1 day.

  • Colon

    Underwater EMR Tops Conventional EMR in RCT of 10- to 20-mm Lesions

    Douglas K. Rex, MD, FASGE reviewing Yamashina T, et al. Gastroenterology 2019 Apr 11.

    Previous studies have suggested that en bloc resection is easier to achieve with underwater endoscopic mucosal resection compared to conventional EMR. This randomized trial compared the two techniques to determine if underwater EMR was better than the conventional method at removing mid-sized polyps.

  • Colon

    Robotic ESD Likely to Be Easier, Faster, Safer for Novices

    Douglas K. Rex, MD, FASGE reviewing De Moura DTH, et al. Gastrointest Endosc 2019 Mar 25.

    Robotic-assisted systems are FDA-approved for endoscopic procedures in the rectum and might improve utilization of endoscopic submucosal dissection (ESD) elsewhere in the GI tract. In a randomized study, ESD novices performed colonic ESDs using a conventional ESD approach without supplemental traction techniques versus robotic-assisted ESD.

  • Colon

    More Simethicone in the Prep Means Less in the Scope

    Douglas K. Rex, MD, FASGE reviewing Moraveji S, et al. Gastrointest Endosc 2019 Mar 26.

    This randomized trial compared a colon preparation agent given to patients split dose with or without simethicone to determine the effect of oral simethicone on polyp and adenoma detection rates, cecal intubation time, and withdrawal time.