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Currently submitted to: JMIR Research Protocols

Date Submitted: Dec 18, 2019
Open Peer Review Period: Dec 17, 2019 - Feb 11, 2020
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Protocol of the DARIO randomized trial: Effects of alternative offers of screening sigmoidoscopy and colonoscopy on utilization and yield of endoscopic screening for colorectal neoplasms

  • Petra Schrotz-King; 
  • Hermann Brenner; 
  • Michael Hoffmeister; 
  • Peter Sauer; 
  • Anja Schaible; 



Flexible sigmoidoscopy and colonoscopy are recommended screening options for colorectal cancer (CRC). Of these options, only colonoscopy which requires complete bowel cleansing and is more invasive but visualizes the entire colon and rectum is offered for CRC screening, but use of this offer has been very limited.


To assess the potential for increasing use of endoscopic CRC screening and the detection of advanced colorectal neoplasms by offering the choice between use of flexible sigmoidoscopy and colonoscopy.


The DARIO study includes a cross-sectional study (Part I), followed by a prospective two-arm randomized controlled intervention trial (Part II) with an associated biobank study (Part III). Participation is possible in part I only, parts I and II, or all three parts. After obtaining informed consent from the municipalities 12,000 people, aged 50-54 years, from the Rhine-Neckar region in Germany are randomly selected from residential lists of the responsible population registries and are invited to complete a standardized questionnaire to investigate the nature, frequency, timing, and results of previous colorectal cancer screening and eventual diagnostic colonoscopies. In study part II participants from study part I with no colonoscopy in the preceding 5 years are randomized into two arms: arm A offering screening colonoscopy only, and arm B offering both options, either screening colonoscopy or screening sigmoidoscopy, to investigate whether the screening offer for less invasive sigmoidoscopy leads to a higher use of endoscopic screening and a higher number of detected and removed neoplasms > 0.5cm (primary endpoint). Part III of the study will use samples from participants in study part II to construct a liquid and tissue biobank for the evaluation of less invasive methods of early detection of colon cancer and for the more detailed characterization of the detected neoplasms. Blood, urine, stool and saliva samples are taken before the endoscopy. Tissue samples are obtained from the neoplasms removed during endoscopy.


10,568 randomly selected women and men aged 50-54 years living in the Rhine-Neckar-Region of Germany have been invited for participation, 1432 could not be invited because they reached the age of 55 at the time of contact, 2789 women and men participated in study part I. Study parts II and III are ongoing.


This study will answer the question if alternative offers of either screening sigmoidoscopy or screening colonoscopy will increase utilization and effectiveness of endoscopic CRC screening compared to an exclusive offer of screening colonoscopy. In addition, alternative non-invasive screening tests will be developed and validated. Clinical Trial: The trial was registered during recruitment of the participants in on September 30, 2019: German Clinical Trials Register DRKS-ID: DRKS0000


Please cite as:

Schrotz-King P, Brenner H, Hoffmeister M, Sauer P, Schaible A

Protocol of the DARIO randomized trial: Effects of alternative offers of screening sigmoidoscopy and colonoscopy on utilization and yield of endoscopic screening for colorectal neoplasms

JMIR Preprints. 18/12/2019:17516

DOI: 10.2196/preprints.17516


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