Diagnostic value of distal colonic polyps for prediction of advanced proximal neoplasia in an average-risk population undergoing screening colonoscopy

Abstract

BACKGROUNDFor colorectal cancer screening, the predictive value of distal findings in the ascertainment of proximal lesions is not fully established. The aims of this study were to assess distal findings as predictors of advanced proximal neoplasia and to compare the predictive value of endoscopy alone vs. combined endoscopic and histopathologic data. METHODSPrimary colonoscopy screening was performed in 2210 consecutive, average-risk adults. Age, gender, endoscopic (size, number of polyps), and histopathologic distal findings were used as potential predictors of advanced proximal neoplasms (i.e., any adenoma ≥1 cm in size, and/or with villous histology, and/or with severe dysplasia or invasive cancer). Polyps were defined as distal if located in the descending colon, the sigmoid colon, or the rectum. Those in other locations were designated proximal. RESULTSNeoplastic lesions, including 11 invasive cancers, were found in 617 (27.9%) patients. Advanced proximal neoplasms without any distal adenoma were present in 1.3% of patients. Of the advanced proximal lesions, 39% were not associated with any distal polyp. Older age, male gender, and distal adenoma were independent predictors of advanced proximal neoplasms. The predictive ability of a model with endoscopic data alone did not improve after inclusion of histopathologic data. In multivariate logistic regression analysis, the predictive ability of models that use age, gender, and any combination of distal findings was relatively low. The proportion of advanced proximal neoplasms identified if any distal polyp was an indication for colonoscopy was only 62%. CONCLUSIONSA strategy in which colonoscopy is performed solely in patients with distal colonic findings is not effective screening for the detection of advanced proximal neoplasms in an average-risk population.Reprint requests: Maite Betés Ibáñez, MD, PhD, Departamento de Digestivo, Clínica Universitaria de Navarra, 31080 Pamplona, Spain. INTRODUCTIONMost colorectal cancers (CRC) develop from adenomas, 1-3 which have a long, asymptomatic phase during which they are detectable and curable. Excision of colorectal adenomas reduces the incidence and the mortality of CRC. 2,4-11 Therefore, CRC fulfills the criteria for benefit from screening. 12 In 1996, the United States Preventive Services Task Force recommended screening of asymptomatic adults over 50 years of age with either flexible sigmoidoscopy (FS) or fecal occult blood tests (FOBT). 13 These recommendations now are endorsed by the American Cancer Society, 14 the World Health Organization, 15 and by virtually all medical and surgical professional societies concerned with digestive diseases. 16,17 A positive FS or FOBT result is an indication for colonoscopy. The continuing high mortality rates for patients with CRC, together with two large studies that demonstrate that FS fails to identify a substantial proportion of proximal lesions, 18,19 have led many specialists to regard reliance on FS or FOBT alone as screening tests would be as wrong as mammography o...

Screening for Colorectal Cancer in Average-Risk Chinese Population Using a Mixed Strategy with Sigmoidoscopy and Colonoscopy

“…5,8,11 However, whether males have more APN than females remains controversial. [19][20][21][22] Our results showed that females tend to have more proximal distribution of advanced colonic neoplasia compared with males (53 vs. 35 percent; P=0.07); however, the prevalence of APN was similar in males and females in each age category (Fig. 2C).…”

Colorectal Cancer Localization in Young Patients: Should We Expand the Screening Program?

“…Based on the results of sigmoidoscopy or occult blood in stool, a decision is made to perform colonoscopy. However, the need to use colonoscopy for primary screening has been demonstrated in 3 large series [15,29,30]. Lieberman et al [29] screened 3196 asymptomatic individuals with colonoscopy.…”

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“…In addition, individuals without adenomas in the distal colon, as shown by sigmoidoscopy, frequently do not receive a follow-up colonoscopy. The percentage of asymptomatic individuals with isolated advanced proximal adenomas or cancer who undergo a colonoscopy is 1.3–5% [58,59]. Atkin et al [60] reported that sigmoidoscopy screening reduces the mortality from CRC.…”