Impact of Fellow Participation During Colonoscopy on Adenoma Detection Rates



An endoscopist’s adenoma detection rate (ADR) is inversely related to interval colorectal cancer risk and cancer mortality. Previous studies evaluating the impact of gastroenterology fellow participation in colonoscopy on ADR have generated conflicting results.


We aimed to determine the impact of fellow participation, duration of fellowship training, and physician sex on ADR and advanced ADR (AADR).


We retrospectively analyzed average-risk patients undergoing screening colonoscopy at Veterans Affairs New York Harbor Healthcare System Brooklyn Campus and Kings County Hospital Center. Review of colonoscopy and pathology reports were performed to obtain adenoma-specific details, including the presence of advanced adenoma and adenoma location (right vs. left colon).


There were 893 colonoscopies performed by attending only and 502 performed with fellow participation. Fellow participation improved overall ADR (44.6% vs. 35.4%, p < 0.001), right-sided ADR (34.1% vs. 25.2%, p < 0.001), and AADR (15.3% vs. 8.3%, p < 0.001); however, these findings were institution-specific. Year of fellowship training did not impact overall ADR or overall AADR, but did significantly improve right-sided AADR (p-value for trend 0.03). Female attending physicians were associated with increased ADR (47.1% vs. 37.0%, p = 0.0037). Fellow sex did not impact ADR.


Fellow participation in colonoscopy improved overall ADR and AADR, and female attending physicians were associated with improved ADR. Year of fellowship training did not impact overall ADR or AADR.

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Adenoma detection rate


Advanced adenoma detection rate


Boston bowel preparation scale


Body mass index


Nonsteroidal anti-inflammatory drug


Veterans Affairs


  1. 1.

    Winawer SJ, Zauber AG, Ho MN et al. Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup. N Engl J Med 1993; 329: 1977–1981

  2. 2.

    Zauber AG, Winawer SJ, O’Brien MJ et al. Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths. N Engl J Med 2012;366:687–696

    CAS  Article  Google Scholar 

  3. 3.

    Corley DA, Jensen CD, Marks AR et al. Adenoma detection rate and risk of colorectal cancer and death. N Engl J Med 2014;370:1298–1306

    CAS  Article  Google Scholar 

  4. 4.

    Kaminski MF, Regula J, Kraszewska E et al. Quality indicators for colonoscopy and the risk of interval cancer. N Engl J Med 2010;362:1795–1803

    CAS  Article  Google Scholar 

  5. 5.

    Rex DK, Schoenfeld PS, Cohen J et al. Quality indicators for colonoscopy. Am J Gastroenterol 2015;110:72–90

    Article  Google Scholar 

  6. 6.

    Mehrotra A, Dellon ES, Schoen RE et al. Applying a natural language processing tool to electronic health records to assess performance on colonoscopy quality measures. Gastrointest Endosc 2012;75:e1214

    Google Scholar 

  7. 7.

    Adler A, Wegscheider K, Lieberman D et al. Factors determining the quality of screening colonoscopy: a prospective study on adenoma detection rates, from 12,134 examinations (Berlin colonoscopy project 3, BECOP-3). Gut 2013;62:236–241

    Article  Google Scholar 

  8. 8.

    Lee TJ, Rees CJ, Blanks RG et al. Colonoscopic factors associated with adenoma detection in a national colorectal cancer screening program. Endoscopy 2014;46:203–211

    Article  Google Scholar 

  9. 9.

    Mehrotra A, Morris M, Gourevitch RA et al. Physician characteristics associated with higher adenoma detection rate. Gastrointest Endosc 2018;87:e775

    Google Scholar 

  10. 10.

    Cadoni S, Falt P, Rondonotti E et al. Water exchange for screening colonoscopy increases adenoma detection rate: a multicenter, double-blinded, randomized controlled trial. Endoscopy 2017;49:456–467

    Article  Google Scholar 

  11. 11.

    Cohen J, Grunwald D, Grossberg LB, Sawhney MS. The effect of right colon retroflexion on adenoma detection: a systematic review and meta-analysis. J Clin Gastroenterol 2017;51:818–824

    Article  Google Scholar 

  12. 12.

    Min M, Deng P, Zhang W et al. Comparison of linked color imaging and white-light colonoscopy for detection of colorectal polyps: a multicenter, randomized, crossover trial. Gastrointest Endosc 2017;86:724–730

    Article  Google Scholar 

  13. 13.

    Chalifoux SL, Rao DS, Wani SB et al. Trainee participation and adenoma detection rates during screening colonoscopies. J Clin Gastroenterol 2014;48:524–529

    Article  Google Scholar 

  14. 14.

    Gianotti RJ, Oza SS, Tapper EB et al. A longitudinal study of adenoma detection rate in gastroenterology fellowship training. Dig Dis Sci 2016;61:2831–2837

    Article  Google Scholar 

  15. 15.

    Peters SL, Hasan AG, Jacobson NB et al. Level of fellowship training increases adenoma detection rates. Clin Gastroenterol Hepatol 2010;8:439–442

    Article  Google Scholar 

  16. 16.

    Qayed E, Shea L, Goebel S et al. Association of trainee participation with adenoma and polyp detection rates. World J Gastrointest Endosc 2017;9:204–210

    Article  Google Scholar 

  17. 17.

    Friedman M, Arora G, Green J. Fellow involvement during colonoscopy does not reduce adenoma detection rate. Dig Dis Sci 2011;56:919

    Article  Google Scholar 

  18. 18.

    Eckardt AJ, Kheder J, Basil A et al. Trainee participation during screening colonoscopy does not affect ADR at subsequent surveillance, but may result in early follow-up. Endosc Int Open 2020;8:E1732–E1740

    Article  Google Scholar 

  19. 19.

    Kim YD, Bae WK, Choi YH et al. Difference in adenoma detection rates according to colonoscopic withdrawal times and the level of expertise. Korean J Gastroenterol 2014;64:278–283

    Article  Google Scholar 

  20. 20.

    Nishizawa T, Suzuki H, Takahashi M et al. Trainee participation during colonoscopy adversely affects polyp and adenoma detection rates. Digestion 2011;84:245–246

    Article  Google Scholar 

  21. 21.

    Facciorusso A, Buccino VR, Tonti P et al. Impact of fellow participation on colon adenoma detection rates: a multicenter randomized trial. Gastrointest Endosc 2020;92:1228–1235

    Article  Google Scholar 

  22. 22.

    Corley DA, Jensen CD, Marks AR et al. Variation of adenoma prevalence by age, sex, race, and colon location in a large population: implications for screening and quality programs. Clin Gastroenterol Hepatol 2013;11:172–180

    Article  Google Scholar 

  23. 23.

    Shrubsole MJ, Wu H, Ness RM et al. Alcohol drinking, cigarette smoking, and risk of colorectal adenomatous and hyperplastic polyps. Am J Epidemiol 2008;167:1050–1058

    Article  Google Scholar 

  24. 24.

    Laiyemo AO, Doubeni C, Sanderson AK 2nd et al. Likelihood of missed and recurrent adenomas in the proximal versus the distal colon. Gastrointest Endosc 2011;74:253–261

    Article  Google Scholar 

  25. 25.

    Tziatzios G, Gkolfakis P, Triantafyllou K. Effect of fellow involvement on colonoscopy outcomes: A systematic review and meta-analysis. Dig Liver Dis 2019;51:1079–1085

    Article  Google Scholar 

  26. 26.

    Barclay RL, Vicari JJ, Doughty AS et al. Colonoscopic withdrawal times and adenoma detection during screening colonoscopy. N Engl J Med 2006;355:2533–2541

    CAS  Article  Google Scholar 

  27. 27.

    Rex DK. Colonoscopic withdrawal technique is associated with adenoma miss rates. Gastrointest Endosc 2000;51:33–36

    CAS  Article  Google Scholar 

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Study was conceptualized and designed by JLA, PJ, KR, EG, SV. Data acquisition was performed by JLA, PJ, KR, FMA, GSC, CL, WK, AL, NG, TC. Data analysis and interpretation was done by JLA, PJ, KR, CAK, SS, RMM, SV. Manuscript was drafted by JLA, PJ. Critical revision of the manuscript for important intellectual content was performed by JLA, PJ, KR, FMA, GSC, CL, WK, AL, NG, TC, CAK, SS, RMM, EG, SV. All authors approved the final manuscript. All authors had access to the study data and reviewed and approved the final manuscript.

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Correspondence to James L. Araujo.

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Araujo, J.L., Jaiswal, P., Ragunathan, K. et al. Impact of Fellow Participation During Colonoscopy on Adenoma Detection Rates. Dig Dis Sci (2021).

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  • Adenoma detection rate
  • Colonoscopy
  • Colorectal neoplasms
  • Colorectal cancer screening
  • Gastroenterology fellowship training