Prospective Study of the Frequency and Size Distribution of Polyps Missed by Colonoscopy

Abstract

An important determinant in interpreting the results of colorectal polyp chemoprevention trials is the rate of polyps missed during colonscopic examination. We prospectively examined 90 patients by tandem colonoscopy performed by two alternating examiners. In 69 (76.7%) patients, 221 neoplastic lesions were documented histologically. Of a total of 58 lesions detected in 31 patients, no neoplastic lesion greater than or equal to 10 mm in size was missed; 16% of diminutive (less than or equal to 5 mm) neoplastic polyps and 12.3% of medium-sized (6-9 mm) neoplastic polyps were missed by the first examiner. We conclude that an experienced colonoscopist will miss about 15% of colorectal neoplastic polyps less than 10 mm in size in the setting of adequate bowel preparation. Large (greater than or equal to 10 mm) polyps were rarely missed, however, with the "miss" rate in our study equal to 0, with a 95% confidence limit of 4.64%.

Maintaining Quality in Endoscopy

“…The miss rates of these markers corroborated the findings of Postic et al identifying synchronous lesions in specimens of resected colon (Postic, Lewin et al 2002) as well as the findings of tandem colonscopy studies which used a second closely sequential colonoscopy to determine the miss rate of the first colonoscopy (Hixson, Fennerty et al 1990;Rex, Cutler et al 1997). The www.intechopen.com higher miss rate for markers placed at the flexures highlights the fact due to the high degree of angulation required to navigate these corners lesions may be missed at these sites even with good technique.…”

“…The decrease in sensitivity of colonoscopy associated with missed adenomas also has implications on surveillance intervals, as guidelines for surveillance interval assume thorough examination of the colon and cannot compensate for disparities in technical expertise between colonoscopists. Tandem colonoscopy studies demonstrated adenoma miss rates ranging from 0-6% for adenomas more than 1cm in size, 12-13% for those between 6-9mm, and 15-27% for those under 5mm (Hixson, Fennerty et al 1990;Rex, Cutler et al 1997). CT-colonography in turn demonstrated miss rates between 12 and 17% for adenomas greater than 1cm in size, indicating that tandem colonoscopies may underestimate the true prevalence of missed lesions (Pickhardt, Nugent et al 2004;Van Gelder, Nio et al 2004).…”

The Impact of Colonoscopy on Colorectal Cancer Incidence and Mortality

“…Tandem endoscopic studies showed miss rates of 0-6% for adenomas 1 cm or larger, and 12-13% for adenomas 6-9 mm in size, and 15-27% for adenomas 5 mm or smaller (Rex et al, 1997;Hixson et al, 1990). When computed tomography colonography (CTC) was used in segmental unblinding to assess polyp detection during colonoscopy, the miss rates increased to 12% for adenomas 1 cm or larger (Pickhardt et al, 2004).…”

Colonoscopia com magnificação de imagem: análise da variação interobservadores para os padrões de criptas e comparação das imagens endoscópicas com os achados histopatológicos

“…Contudo, deve-se considerar a possibilidade da não-detecção de lesões polipóides (4,5,6) , a existência de lesões planas diminutas que apresentam comportamento biológico mais agressivo em relação as polipóides do mesmo tamanho (7,8,9,10) ou, então, presença de carcinomas precoces plano-deprimidos que podem ser invasivos, mesmo quando muito pequenos (11,12).…”