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OBJECTIVEThe use of colonoscopy as a primary screening test for colorectal cancer (CRC) in average risk adults is a subject of controversy. Our primary objective was to build a predictive model based on a few simple variables that could be used as a guide for identifying average risk adults more suitable for examination with colonoscopy as a primary screening test. METHODSThe prevalence of advanced adenomas was assessed by primary screening colonoscopy in 2210 consecutive adults at least 40 yr old, without known risk factors for CRC. Age, gender, and clinical and biochemical data were compared among people without adenomas, those with nonadvanced adenomas, and those with any advanced neoplasm. A combined score to assess the risk of advanced adenomas was built with the variables selected by multiple logistic regression analysis. RESULTSNeoplastic lesions were found in 617 subjects (27.9%), including 259 with at least one neoplasm that was 10 mm or larger, villous, or with moderate-to-severe dysplasia, and 11 with invasive cancers. Advanced lesions were more frequent among men, older people, and those with a higher body mass index (BMI). These three variables were independent predictors of advanced adenomas in multivariate analysis. A score combining age, sex, and BMI was developed as a guide for identifying individuals more suitable for screening colonoscopy. CONCLUSIONSAge, gender, and BMI can be used to build a simple score to select those average risk adults who might be candidates for primary screening colonoscopy.Reprint requests and correspondence: Maria Teresa Betés Ibáñez, M.D. Departamento de Digestivo, Clínica Universitaria de Navarra 31080 Pamplona, Spain. INTRODUCTIONColorectal cancer (CRC) is the second most frequent cause of cancer-related death in western countries (1). Most cancers develop from benign adenomatous polyps (2, 3), in subjects with no known risk factors for the disease (4). Although it is not yet possible to determine which adenomas will progress to cancer, certain pathological features have been found to correlate with the risk of progressing to CRC (3, 5). "Advanced adenomas" have been defined as those with at least one of the following characteristics: size 1 cm or larger, tubulovillous or villous histology, and moderate or severe dysplasia (6-9).Screening with full colonoscopy as a primary procedure has been limited to a few small series (10-16), and results have not been focused in advanced adenomas. Two large colonoscopic series recently published (17,18) have assessed the proportion of advanced proximal adenomas in average risk adults. Although the prevalence of colonic adenomas is higher among men than among women (5,12,19,20) and increases with age (11,13,15), more data are needed to adequately assess the independent role of the most relevant predictors of advanced adenomas (18). A variety of factors have been linked to the development of adenomas or CRC (21-25), but currently there is no dominant risk factor that could be practically used for risk stratification in screening...

Purpose: The present study aimed to determine the prevalence of MUTYH mutations in patients with multiple colonic polyps and to explore the best strategy for diagnosing MUTYH-associated polyposis (MAP) in these patients.Experimental Design: This study included 405 patients with at least 10 colonic polyps each. All cases were genetically tested for the three most frequent MUTYH mutations. Whole-gene analysis was performed in heterozygous patients and in 216 patients lacking the three most frequent mutations. Polyps from 56 patients were analyzed for the KRAS-Gly12Cys and BRAF V600E somatic mutations.Results: Twenty-seven (6.7%) patients were diagnosed with MAP, of which 40.8% showed serrated polyps. The sensitivity of studying only the three common variants was 74.1%. Of 216 patients without any monoallelic mutation in common variants, whole-gene analysis revealed biallelic pathogenic mutation in only one. G396D mutation was associated with serrated lesions and older age at diagnosis. There was a strong association between germinal MUTYH mutation and KRAS Gly12Cys somatic mutation in polyps. BRAF V600E mutation was found in 74% of serrated polyps in MUTYH-negative patients and in none of the polyps of MAP patients.Conclusions: We observed a low frequency of MUTYH mutations among patients with multiple adenomatous and serrated polyps. The MAP phenotype frequently included patients with serrated polyps, especially when G396D mutation was involved. Our results show that somatic molecular markers of polyps can be useful in identifying MAP cases and support the need for the complete MUTYH gene analysis only in patients heterozygous for recurrent variants.

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The risk of CRC in patients with multiple serrated polyps who do not meet the criteria for serrated polyposis, and in their first-degree relatives, is similar to that of patients diagnosed with serrated polyposis.

This article has an accompanying continuing medical education activity, also eligible for MOC credit, on page e65. Learning Objective-Upon completion of this activity, successful learners will be able to name the indication for colonoscopy associated with the lowest rate of adequate colon cleansing; list the indications for colonoscopy associated with the highest adenoma detection rates; name the indication for endoscopic evaluation that has the highest advanced adenoma detection rate; list the indication for colonoscopy associated with the highest colorectal cancer detection rate.

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