Location of adenomas missed by optical colonoscopy.
BACKGROUND
Previous estimates of the adenoma miss rate with optical colonoscopy (OC) are hindered by the use of OC as its own reference standard.


OBJECTIVE
To evaluate the frequency and characteristics of colorectal neoplasms that are missed prospectively on OC by using virtual colonoscopy (VC) as a separate reference standard.


METHODS
Prospective, multicenter screening trial.


METHODS
3 medical centers.


METHODS
1233 asymptomatic adults who underwent same-day VC and OC.


METHODS
Colorectal neoplasms (adenomatous polyps) missed at OC before VC results were unblinded.


RESULTS
Fourteen (93.3%) of 15 nonrectal neoplasms were located on a fold; 10 (71.4%) of these were located on the backside of a fold. Five (83.3%) of 6 rectal lesions were located within 10 cm of the anal verge.


CONCLUSIONS
Estimation of the OC miss rate depended on polyp detection on both VC and second-look OC and therefore underestimates the true OC miss rate, particularly for smaller polyps.


CONCLUSIONS
Most clinically significant adenomas missed prospectively on OC are located behind a fold or near the anal verge. The 12% OC miss rate for large adenomas (>or=10 mm) when state-of-the-art 3-dimensional VC is used as a separate reference standard is increased from the previous 0% to 6% estimates derived by using OC as its own reference standard.
Pickhardt
Perry J
PJ
Department of Radiology, University of Wisconsin Medical School, E3/311 Clinical Science Center, 600 Highland Avenue, Madison, WI 53792-3252, USA. ppickhardt@mail.radiology.wisc.edu
Nugent
Pamela A
PA
Mysliwiec
Pauline A
PA
Choi
J Richard
JR
Schindler
William R
WR
D000236:Adenoma / Q000473:pathology*; D000328:Adult; D023881:Colonography, Computed Tomographic; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007417:Intestinal Polyps / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies