Background: During colonoscopy, correct assessment of polyps is important. Recognition
of early carcinomas is needed for tailor-made treatment and avoidance of unnecessary
complications. Moreover, accurate diagnosis of diminutive lesions could result in
a safe resect
and discard strategy. We assessed the accuracy of polyp assessment by general endoscopists
without specific training or experience in image-enhanced endoscopy during routine
colonoscopies within a fecal immunochemical test (FIT)-based screening program.
Methods: Data were collected in the third round of a FIT-based colorectal cancer
screening pilot program. Patients diagnosed as FIT-positive (318) underwent colonoscopy
using
Olympus (160 and 180 series) endoscopes without magnification or routine use of (virtual)
chromoendoscopy. Endoscopists received no special training. They made an on-site evaluation
and
classified detected polyps as hyperplastic, adenoma, carcinoma. Samples of resected
lesions
were sent for histopathology. Sensitivity and specificity were calculated. We differentiated
for fellows and consultants.
Results: In the 318 patients with a positive FIT-screening result, 683 lesions were
detected; 564 lesions were included in the analyses. The pathologist classified these
lesions
as 141 hyperplastic polyps, 349 adenomas, 16 carcinomas, and 58 other. Sensitivity
for
diagnosis of adenomas was 88 % (95 %CI 84 – 91); specificity 49 % (95 %CI 42 – 55).
Of the 16
colorectal carcinomas, endoscopists diagnosed four incorrectly (sensitivity 75 % [95 %CI
44 – 89]; specificity 99 % [95 %CI 98 – 100]), including three stage I cancers and
one stage
III cancer. There were no differences in accuracy of diagnosis that related to different
sizes
of lesions or the experience of the endoscopist.
Conclusion: In a routine FIT-based screening setting and without specific training or
routine use of (digital) chromoendoscopy, endoscopic prediction of the histopathology
of
colonic lesions is inaccurate when the procedure is performed by general endoscopists.
