Assessment of Miss and Incidence Rates of Neoplastic Polyps at Colonoscopy

Abstract

Background : The incidence rate after a colonoscopic polypectomy includes the true incidence rate of new polyp formation and miss rate of polyps at the initial colonoscopy. It is therefore important to assess accurate incidence rates of polyps as well as those of missing polyps with colocoscopy. Methods : Six hundred and eighty-eight patients who underwent total colonoscopy twice within 30 days were investigated to determine the miss rates of neoplastic polyps under colonoscopy. The cumulative incidence rates of neoplasm were evaluated by the Kaplan-Meier method in another series of investigations on 864 patients who underwent surveillance total colonoscopy over 31 days. Results : In 157 (22.8%) patients out of 688, 200 neoplastic lesions (all adenomas) were missed during the first examination. The miss rate was 16% for adenomas £ 5 mm and 2% for adenomas > 10 mm. The miss rates of patients with 0, 1, 2, or > 2 neoplastic polyps on the first examination was 5.3%, 19.6%, 23.5% and 35.5%, respectively. One year cumulative incidence rates of patients with 1, 2, or > 2 neoplastic polyps on the first examination were 18.4%, 21.1% and 34.2%, respectively. Conclusion : Detection of multiple neoplasms on index colonoscopy predicts a high miss rate and cumulative incidence rate on surveillance colonoscopy. A substantial proportion of neoplasms detected at nearly 1-year postpolypectomy surveillance colonoscopy were missed at the initial total colonoscopy.

Colonoscopy surveillance after polypectomy

“…Miss rates according to the number of polyps found on first examination were 5.3% for none, 19.6% for one, 23.5% for two and 35.5% for C3 polyps detected on first examination. The OR for finding adenomas on the second examination was higher for patients with C2 adenomas on first examination (OR 2.06, 95% CI 1.42-3.00) than for those of 0 or 1 adenomas on first examination [28]. Other studies demonstrated similar findings with patients showing 1, 2 or C3 detected adenomas on initial colonoscopy, with miss rates of 17%, 29% and 42%, respectively, in one report [55], and 30%, 48% and 47%, respectively, in a second report [23].…”

“…A total of 17% of patients had C1 neoplastic polyp missed on initial examination. Another large study involved 688 patients who underwent total colonoscopy twice within 30 days [28]. In 157 of 688 patients (22.8%), 200 neoplastic lesions (all adenomas) were missed during the first examination.…”

“…Especially in Japan, high-resolution colonoscopy and chromoendoscopy have been used to improve the ability to detect non-polypoid lesions during colonoscopy [14,50]. Miss rates for flat-or depressed-type adenomas are known to be higher than for polypoid lesions [27,28]. In a Japanese retrospective study, 554 patients underwent at least two colonoscopies that took particular care not to miss any polyps or depressed adenomas on the first colonoscopy, then searched for flat early cancers developing in polypfree colorectal mucosa on and after the second colonoscopy [51].…”

Investigation of Undetected Small Bowel Tumors on Capsule Endoscopy

“…For the colon, the colonoscopy has been reported to have a failure rate of 22.8% to 26.0% for detecting lesions [20,21] compared with 16% to 33.4% for colonic CE [22,23] . According to these reports, the reasons for detection failure on colonoscopy and CE of the colon include the following: the lesion being hidden by the folds of the large intestine, bowel residue, or feces; technical issues, such as the probe being pulled out suddenly and preventing complete observation; or missing the lesion.…”

La fréquence des cancers coliques d’intervalle est-elle le seul critère pertinent pour la coloscopie ?

“…Parmi les cinq études incluses dans cette méta-analyse, trois montrent que la moitié des faux-négatifs siègent sur le côlon distal : 21 parmi 45 polypes omis siégeaient entre l'angle gauche ou le sigmoïde [22], cette proportion variait de 13/22 [23] à 87/200 [24]. Ainsi, le RR de polypes omis, selon la localisation décrite que dans deux études, n'était pas significativement augmenté dans le côlon proximal : 1,2 (IC 95 % : [0,9-1,6]) [24] ou 1,2 (IC 95 % : [0,6-2,2]) [8].…”