Retrograde-viewing device improves adenoma detection rate in colonoscopies for surveillance and diagnostic workup.
OBJECTIVE
To determine which patients might benefit most from retrograde viewing during colonoscopy through subset analysis of randomized, controlled trial data.


METHODS
The Third Eye® Retroscope® Randomized Clinical Evaluation (TERRACE) was a randomized, controlled, multicenter trial designed to evaluate the efficacy of a retrograde-viewing auxiliary imaging device that is used during colonoscopy to provide a second video image which allows viewing of areas on the proximal aspect of haustral folds and flexures that are difficult to see with the colonoscope's forward view. We performed a post-hoc analysis of the TERRACE data to determine whether certain subsets of the patient population would gain more benefit than others from use of the device. Subjects were patients scheduled for colonoscopy for screening, surveillance or diagnostic workup, and each underwent same-day tandem examinations with standard colonoscopy (SC) and Third Eye colonoscopy (TEC), randomized to SC followed by TEC or vice versa.


RESULTS
Indication for colonoscopy was screening in 176/345 subjects (51.0%), surveillance after previous polypectomy in 87 (25.2%) and diagnostic workup in 82 (23.8%). In 4 subjects no indication was specified. Previously reported overall results had shown a net additional adenoma detection rate (ADR) with TEC of 23.2% compared to SC. Relative risk (RR) of missing adenomas with SC vs TEC as the initial procedure was 1.92 (P = 0.029). Post-hoc subset analysis shows additional ADRs for TEC compared to SC were 4.4% for screening, 35.7% for surveillance, 55.4% for diagnostic and 40.7% for surveillance and diagnostic combined. The RR of missing adenomas with SC vs TEC was 1.11 (P = 0.815) for screening, 3.15 (P = 0.014) for surveillance, 8.64 (P = 0.039) for diagnostic and 3.34 (P = 0.003) for surveillance and diagnostic combined. Although a multivariate Poisson regression suggested gender as a possibly significant factor, subset analysis showed that the difference between genders was not statistically significant. Age, bowel prep quality and withdrawal time did not significantly affect the RR of missing adenomas with SC vs TEC. Mean sizes of adenomas detected with TEC and SC were similar at 0.59 cm and 0.56 cm, respectively (P = NS).


CONCLUSIONS
TEC allows detection of significantly more adenomas compared to SC in patients undergoing surveillance or diagnostic workup, but not in screening patients (ClinicalTrials.gov Identifier: NCT01044732).
Department of Gastroenterology and Hepatology, University Medical Center Utrecht, 3508 GA Utrecht, The Netherlands. p.d.siersema@umcutrecht.nl
Peter D
PD
Siersema
Amit
A
Rastogi
Anke M
AM
Leufkens
Paul A
PA
Akerman
Kassem
K
Azzouzi
Richard I
RI
Rothstein
Frank P
FP
Vleggaar
Alessandro
A
Repici
Giacomo
G
Rando
Patrick I
PI
Okolo
Olivier
O
Dewit
Ana
A
Ignjatovic
Elizabeth
E
Odstrcil
James
J
East
Pierre H
PH
Deprez
Brian P
BP
Saunders
Anthony N
AN
Kalloo
Bradley
B
Creel
Vikas
V
Singh
Anne Marie
AM
Lennon
Daniel C
DC
DeMarco
D000236:Adenoma / Q000175:diagnosis* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003113:Colonoscopy / Q000379:methods*; D055088:Early Detection of Cancer; D019723:Endoscopes; D005260:Female; D006801:Humans; D008297:Male; D008495:Medical Oncology / Q000379:methods*; D008875:Middle Aged; D015999:Multivariate Analysis; D012044:Regression Analysis; D015203:Reproducibility of Results