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Original research
Multicentre, prospective, randomised study comparing the diagnostic yield of colon capsule endoscopy versus CT colonography in a screening population (the TOPAZ study)
  1. Brooks D Cash1,
  2. Mark R Fleisher2,
  3. Steven Fern3,
  4. Elizabeth Rajan4,
  5. Robyn Haithcock5,
  6. David M Kastenberg6,
  7. David Pound7,
  8. Neofytos P Papageorgiou8,
  9. Ignacio Fernández-Urién9,
  10. Ira J Schmelkin10,
  11. Douglas K Rex11
  1. 1Gastroenterology, University of Texas Health Science Center at Houston, Houston, Texas, USA
  2. 2Gastroenterology, Borland Groover Clinic, Jacksonville, Florida, USA
  3. 3Specialists in Gastroenterology, Clinical Research Professionals, Saint Louis, Missouri, USA
  4. 4Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
  5. 5MultiCare Medical Division Gastroenterology, Clinical Research Professionals, Chesterfield, Missouri, USA
  6. 6Gastroenterology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA
  7. 7Indianapolis Gastroenterology and Hepatology, Indianapolis, Indiana, USA
  8. 8Gastroenterology, American Medical Center, Nicosia, Cyprus
  9. 9Department of Gastroenterology and Hepatology, Complejo Hospitalario de Navarra, Pamplona, Navarra, Spain
  10. 10Gastroenterology, Baystate Medical Center, Springfield, Massachusetts, USA
  11. 11Indiana University School of Medicine, Indiana University Hospital, Indianapolis, Indiana, USA
  1. Correspondence to Dr Brooks D Cash, Gastroenterology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;{at}


Objective Colon capsule endoscopy (CCE) has shown promise for colorectal neoplasia detection compared with optical colonoscopy (OC), but has not been compared with other screening tests in average risk screening patients.

Design Patients 50 to 75 years of age (African Americans, 45–75 years) were randomised to CCE or CT colonography (CTC) and subsequent blinded OC. The primary endpoint was diagnostic yield of polyps ≥6 mm with CCE or CTC. Secondary endpoints included accuracy for size and histology, examination completeness, number/proportion of subjects with polyps and adenomas ≥6 mm and ≥10 mm, subject satisfaction and safety.

Results From 320 enrolled subjects, data from 286 (89.4%) were evaluable. The proportion of subjects with any polyp ≥6 mm confirmed by OC was 31.6% for CCE versus 8.6% for CTC (pPr non-inferiority and superiority=0.999). The diagnostic yield of polyps ≥10 mm was 13.5% with CCE versus 6.3% with CTC (pPr non-inferiority=0.9954). The sensitivity and specificity of CCE for polyps ≥6 mm was 79.2% and 96.3% while that of CTC was 26.8% and 98.9%. The sensitivity and specificity of CCE for polyps ≥10 mm was 85.7% and 98.2% compared with 50% and 99.1% for CTC. Both tests were well tolerated/safe.

Conclusion CCE was superior to CTC for detection of polyps ≥6 mm and non-inferior for identification of polyps ≥10 mm. CCE should be considered comparable or superior to CTC as a colorectal neoplasia screening test, although neither test is as effective as OC.

Trial registration number no: NCT02754661.

  • colorectal cancer screening
  • endoscopic procedures
  • colonic adenomas
  • colonic polyps

Statistics from


  • Contributors Study concept: BDC, DKR, MRF, DMK. Study design: BDC, DKR, DMK. Acquisition of data: BDC, DKR. Analysis of data: BDC, DKR. Interpretation of data: BDC, DKR. Drafting of the manuscript: BDC, DKR. Critical revision of the manuscript for important intellectual content: BDC, MRF, SF, ER, RH, DMK, DP, NPP, IF-U, DKR. Approval of the final version of the manuscript: BDC, MRF, SF, ER, RH, DMK, DP, NPP, IF-U, IJS, DKR.

  • Funding This study was sponsored and funded by Medtronic.

  • Competing interests These authors disclose the following: BDC: Consultant to Medtronic, Salix, Allergan, Takeda; Speakers’ Bureau for Salix, Allergan, Takeda, AlfaSigma, RedHill, QOL. ER: Consultant to Olympus; IP with Medtronic. DMK: Consultant to Medtronic, Ferring, Salix, MotusGI; Research support from Medtronic, MotusGI. DP: Speakers’ Bureau: Gilead Life Sciences, Merck; Advisory Boards: Gilead, Novartis, Intercept. NPP: Consultant to Medtronic. IF-U received honorarium from Medtronic. IJS: Consultant to Medtronic. DKR: Consultant to Olympus Corporation, Boston Scientific, Medtronic, Aries Pharmaceutical, Braintree Laboratories, Lumendi Ltd, Norgine, Endokey, GI Supply; Research support: EndoAid, Olympus Corporation, Medivators, Erbe USA Inc.; Ownership: Satisfai Health.

  • Patient consent for publication Not required.

  • Ethics approval This study was approved by institutional review boards at each centre.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data may be obtained from a third party and are not publicly available. The study protocol, statistical analysis plan and study results are available on ( Individual participant data are not available for sharing.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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