Abstract
Background and Aims
Most studies reporting polyp size use visual estimates. Determining the prevalence of advanced histology based on direct measurement of polyp size may help guide the management of polyps found at optical colonoscopy (OC) and CT colonography (CTC).
Methods
We designed a large, prospective study to assess the prevalence of advanced adenomas based on direct measurement of polyp size by a certified pathologists’ assistant as reported in the pathology report. Patients between 40 and 89 years of age who presented for screening colonoscopy were included in our study. Advanced adenomas were defined as ≥10 mm or ≥25% villous features, high grade dysplasia or cancer. Polyps were divided by size into three groups: diminutive (≤5 mm), small (6–9 mm) and large (≥10 mm). If more than one adenoma was present, the most advanced was used for analysis.
Results
We evaluated 6,905 consecutive patients referred for colonoscopy between January 2005 and December 2006. Of the 4,967 who met the inclusion criteria, the mean age was 58.8 and consisted of 59% women. Overall, 930 (18.7%) had an adenoma; 248 (5%) were advanced adenomas including 8 (0.16%) cancers. Of 89 polyps ≥10 mm, 76 (85%) had advanced histology; of 247 polyps 6–9 mm, 67 (27%) were advanced; of 1,025 polyps ≤5 mm, 105 (10%) were advanced. Thus, 172 of 248 (69%) patients with advanced adenomas had small or diminutive adenomas.
Conclusions
Our data indicate the majority (69%) of advanced adenomas are <10 mm. Even among polyps ≤5 mm, there was an appreciable prevalence of advanced adenomas (10%). These findings may help guide the management of sub-centimeter colon polyps found by OC or CTC.
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References
Lieberman DA, Weiss DG, Bond JH, et al. Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans affairs cooperative study group 380. N Engl J Med. 2000;343:162–168.
Imperiale TF, Wagner DR, Lin CY, et al. Risk of advanced proximal neoplasms in asymptomatic adults according to the distal colorectal findings. N Engl J Med. 2000;343:169–174.
Schoenfeld P, Cash B, Flood A, et al. Colonoscopic screening of average-risk women for colorectal neoplasia. N Engl J Med. 2005;352:2061–2068.
Regula J, Rupinski M, Kraszewska E, et al. Colonoscopy in colorectal-cancer screening for detection of advanced neoplasia. N Engl J Med. 2006;355:1863–1872.
Lieberman D, Moravec M, Holub J, et al. Polyp size and advanced histology in patients undergoing colonoscopy screening: implications for CT colonography. Gastroenterology. 2008;135:1100–1105.
Schoen RE, Gerber LD, Margulies C. The pathologic measurement of polyp size is preferable to the endoscopic estimate. Gastrointest Endosc. 1997;46:492–496.
Morales TG, Sampliner RE, Garewal HS, et al. The difference in colon polyp size before and after removal. Gastrointest Endosc. 1996;43:25–28.
Gopalswamy N, Shenoy VN, Choudhry U, et al. Is in vivo measurement of size of polyps during colonoscopy accurate? Gastrointest Endosc. 1997;46:497–502.
Fennerty MB, Davidson J, Emerson SS, et al. Are endoscopic measurements of colonic polyps reliable? Am J Gastroenterol. 1993;88:496–500.
Scripps Clinic. Regional population percentages from Scripps Clinic Registration Department. La Jolla, CA; Scripps Clinic, 2010.
Strum WB. Incidence of advanced adenomas of the rectosigmoid colon three years and five years after negative flexible sigmoidoscopy in 401 patients. Dig Dis Sci. 2003;48:2278–2283.
Strum WB. Impact of a family history of colorectal cancer on the prevalence of advanced adenomas of the rectosigmoid colon at flexible sigmoidoscopy in 3,147 asymptomatic patients. Dig Dis Sci. 2006;51:2048–2052.
Strum WB. Impact of a family history of colorectal cancer on age at diagnosis, anatomic location, and clinical characteristics of colorectal cancer. Int J Gastro Cancer. 2005;35:121–126.
Kim DH, Pickhardt PJ, Taylor AJ. Characteristics of advanced adenomas detected at CT colonography screening: implications for appropriate polyp size thresholds for polypectomy versus surveillance. Am J Roentgenol. 2007;188:940–944.
O’Brien MJ, Winawer SJ, Zauber AG, et al. The National Polyp Study. Patient and polyp characteristics associated with high-grade dysplasia in colorectal adenomas. Gastroenterology. 1990;98:371–379.
Sciallero S, Bonelli L, Aste H, et al. Do patients with rectosigmoid adenomas 5 mm or less in diameter need total colonoscopy? Gastrointest Endosc. 1999;50:314–321.
Butterly LF, Chase MP, Pohl H, et al. Prevalence of clinically important histology in small adenomas. Clin Gastroenterol Hepatol. 2006;4:343–348.
Pinsky PF, Schoen RE, Weissfeld JL, et al. The yield of surveillance colonoscopy by adenoma history and time to examination. Clin Gastroenterol Hepatol. 2009;7:86–92.
Schoenfeld P, Shad J, Ormseth E, et al. Predictive value of diminutive colonic adenoma trial: the PREDICT trial. Clin Gastroenterol Hepatol. 2003;1:195–201.
Gupta S, Durkalski V, Cotton P, et al. Variation of agreement in polyp size measurement between computed tomographic colonography and pathology assessment: clinical implications. Glin Gastroenterol Hepatol. 2008;6:220–227.
Pickhardt PJ, Hain KS, Kim DH, et al. Low rates of cancer or high-grade dysplasia in colorectal polyps collected from computed tomography colonography screening. Clin Gastroenterol Hepatol. 2010;8:610–615.
Levin B, Lieberman DA, McFarland B, et al. Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. Gastroenterology. 2008;134:1570–1595.
McFarland EG, Levin B, Lieberman DA, et al. Revised colorectal screening guidelines: joint effort of the American Cancer Society. US Multisociety Task Force on Colorectal Cancer, and American College of Radiology. Radiology. 2008;248:717–720.
Hur C, Chung DC, Schoen RE, et al. The management of small polyps found by virtual colonoscopy: results of a decision analysis. Clin Gastroenterol Hepatol. 2007;5:237–244.
Stryker SJ, Wolff BG, Culp CE, et al. Natural history of untreated colonic polyps. Gastroenterology. 1987;93:1009–1013.
Acknowledgments
The authors are grateful for the diligent work of Irving C. Sandbakken, Karin Wheeler and Sharon Reid who assisted in collecting the data, Anne Feng and Dr James Koziol who provided expert statistical assistance, and our colleagues who performed the colonoscopic examinations. This study was supported by private donations to the Scripps Clinic Colorectal Cancer Research Study Program.
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Tsai, F.C., Strum, W.B. Prevalence of Advanced Adenomas in Small and Diminutive Colon Polyps Using Direct Measurement of Size. Dig Dis Sci 56, 2384–2388 (2011). https://doi.org/10.1007/s10620-011-1598-x
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DOI: https://doi.org/10.1007/s10620-011-1598-x