Routine colonoscopies miss more than 10% of polyps
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《英国医生杂志》
A study of adults who did not have signs of colon disease found that traditional optical (flexible) colonoscopies missed more than a tenth of precancerous polyps that were identifiable with virtual colonoscopy, a new "virtual" procedure using computed tomography to form three dimensional images of the colon.
In the study, researchers led by Dr Perry Pickhardt of the University of Wisconsin Medical School, Madison, evaluated 1233 asymptomatic adults (mean age 57.8 years) who had virtual colonoscopy and optical colonoscopy on the same day ( Annals of Internal Medicine 2004;141: 352-9).
The study identified 1310 polyps at optical colonoscopy, 511 (39%) of which measured 5 mm or greater.
Of these 511 polyps, 55 (11%) were found only on "second look" optical colonoscopy, after unblinding of the virtual colonoscopy results. Twenty four (44%) of these 55 lesions were non-adenomatous, including 16 hyperplastic polyps. Of the 31 missed neoplasms, 10 adenomas that measured only 5 mm were excluded from further analysis because of their diminutive size.
Adenomas in the colon (above) are more likely to be missed in certain locations, such as behind a fold or near the anal verge
Credit: DAVID M MARTIN/SPL
The 21 missed adenomas measuring more than 6 mm occurred in 20 patients (17 men and 3 women; mean age 58.2 years).
Thus the "miss" rate for adenomas on optical colonoscopy compared with virtual colonoscopy was 10.0% (95% confidence interval 6.3% to 14.9%) (21 of 210 adenomas measuring 6 mm or more).
At 8 mm and 10 mm thresholds, the adenoma miss rates on optical colonoscopy were 10.5% (5.2% to 18.5%) (10 of 95 adenomas) and 11.8% (4.4% to 23.9%) (6 of 51 adenomas) respectively.
Most clinically important adenomas that were missed on optical colonoscopy were located behind a fold or near the anal verge.
An accompanying editorial in the same issue (pp 401-3) notes that the study relied on a state of the art computed tomography scanner for performance of the virtual colonoscopy that is not available in most centres, as well as using radiologists specially trained in this technique.
"Optical colonoscopy is a sensitive diagnostic tool for detecting colorectal neoplasia. However, despite the utmost attention to technique, even experienced colonoscopists will occasionally miss significant lesions," the authors wrote. "By using VC as a separate standard of reference, our study confirms that distinct locations on OC examination represent relative blind spots where clinically significant polyps can sometimes be missed."(Scott Gottlieb)
In the study, researchers led by Dr Perry Pickhardt of the University of Wisconsin Medical School, Madison, evaluated 1233 asymptomatic adults (mean age 57.8 years) who had virtual colonoscopy and optical colonoscopy on the same day ( Annals of Internal Medicine 2004;141: 352-9).
The study identified 1310 polyps at optical colonoscopy, 511 (39%) of which measured 5 mm or greater.
Of these 511 polyps, 55 (11%) were found only on "second look" optical colonoscopy, after unblinding of the virtual colonoscopy results. Twenty four (44%) of these 55 lesions were non-adenomatous, including 16 hyperplastic polyps. Of the 31 missed neoplasms, 10 adenomas that measured only 5 mm were excluded from further analysis because of their diminutive size.
Adenomas in the colon (above) are more likely to be missed in certain locations, such as behind a fold or near the anal verge
Credit: DAVID M MARTIN/SPL
The 21 missed adenomas measuring more than 6 mm occurred in 20 patients (17 men and 3 women; mean age 58.2 years).
Thus the "miss" rate for adenomas on optical colonoscopy compared with virtual colonoscopy was 10.0% (95% confidence interval 6.3% to 14.9%) (21 of 210 adenomas measuring 6 mm or more).
At 8 mm and 10 mm thresholds, the adenoma miss rates on optical colonoscopy were 10.5% (5.2% to 18.5%) (10 of 95 adenomas) and 11.8% (4.4% to 23.9%) (6 of 51 adenomas) respectively.
Most clinically important adenomas that were missed on optical colonoscopy were located behind a fold or near the anal verge.
An accompanying editorial in the same issue (pp 401-3) notes that the study relied on a state of the art computed tomography scanner for performance of the virtual colonoscopy that is not available in most centres, as well as using radiologists specially trained in this technique.
"Optical colonoscopy is a sensitive diagnostic tool for detecting colorectal neoplasia. However, despite the utmost attention to technique, even experienced colonoscopists will occasionally miss significant lesions," the authors wrote. "By using VC as a separate standard of reference, our study confirms that distinct locations on OC examination represent relative blind spots where clinically significant polyps can sometimes be missed."(Scott Gottlieb)