A simple tissue-handling technique performed in the endoscopy suite improves histologic section quality and diagnostic accuracy for serrated polyps

Background and study aims: Surveillance intervals after colonoscopic resection of serrated polyps are partially predicated on the histology of the polyp(s) removed during the index exam. Histologic discrimination between sessile serrated adenomas/polyps (SSA/P) and hyperplastic polyps is challenging. We devised and tested a simple tool – an envelope – that gastroenterologists can integrate into routine colonoscopy practice to address this problem.

Methods: In the “modified protocol,” immediately after polypectomy each serrated polyp was flattened and enclosed in a paper envelope before being placed in formalin. In the pathology laboratory, each polyp was sectioned after processing. A two-site, prospective, randomized, single-blinded trial was performed to compare this modified protocol with the conventional protocol. Serrated polyps located proximal to the splenic flexure and 5 – 20 mm in diameter were included. A novel orientation score that measured the number of well-oriented crypts per unit area of polyp (higher orientation score = better orientation) was validated. Orientation score, SSA/P diagnosis rate, and inter-pathologist agreement were measured.

Results: A total of 375 polyps were enrolled, of which 264 were identified for analysis. The mean orientation scores in the modified and conventional protocol groups were 3.11 and 1.13, respectively (P < 0.0001). SSA/Ps were diagnosed in 103/135 cases (76.3 %) in the modified protocol group vs. 54/129 (41.9 %) in the conventional protocol group (P < 0.0001). Inter-pathologist agreement was higher with the modified than the conventional protocol (77.0 % vs. 62.8 %; P = 0.015).

Conclusion: Standard polyp handling techniques may be sub-optimal for interpretation of serrated polyps resected at colonoscopy, and may lead to inadvertent histologic “under-grading” of many lesions. Our intervention improved histopathologic interpretation and increased the SSA/P diagnosis rate.

• References

• 1 Zauber AG, Winawer SJ, O’Brien MJ et al. Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths. N Engl J Med 2012; 366: 687-696
• 2 Jass JR, Biden KG, Cummings MC et al. Characterisation of a subtype of colorectal cancer combining features of the suppressor and mild mutator pathways. J Clin Pathol 1999; 52: 455-460
• 3 East JE, Saunders BP, Jass JR. Sporadic and syndromic hyperplastic polyps and serrated adenomas of the colon: classification, molecular genetics, natural history, and clinical management. Gastroenterol Clin North Am 2008; 37: 25-46, v
• 4 Torlakovic E, Skovlund E, Snover DC et al. Morphologic reappraisal of serrated colorectal polyps. Am J Surg Pathol 2003; 27: 65-81
• 5 Groff RJ, Nash R, Ahnen DJ. Significance of serrated polyps of the colon. Curr Gastroenterol Rep 2008; 10: 490-498
• 6 Hiraoka S, Kato J, Fujiki S et al. The presence of large serrated polyps increases risk for colorectal cancer. Gastroenterology 2010; 139: 1503-1510 , e1501–1503
• 7 Oono Y, Fu K, Nakamura H et al. Progression of a sessile serrated adenoma to an early invasive cancer within 8 months. Dig Dis Sci 2009; 54: 906-909
• 8 Snover DC, Jass JR, Fenoglio-Preiser C et al. Serrated polyps of the large intestine: a morphologic and molecular review of an evolving concept. Am J Clin Pathol 2005; 124: 380-391
• 9 Huang CS, Farraye FA, Yang S et al. The clinical significance of serrated polyps. Am J Gastroenterol 2011; 106: 229-240
• 10 Messick CA, Church J, Casey G et al. Identification of the methylator (serrated) colorectal cancer phenotype through precursor serrated polyps. Dis Colon Rectum 2009; 52: 1535-1541
• 11 Hawkins NJ, Ward RL. Sporadic colorectal cancers with microsatellite instability and their possible origin in hyperplastic polyps and serrated adenomas. J Natl Cancer Inst 2001; 93: 1307-1313
• 12 Lu FI, van Niekerk de W, Owen D et al. Longitudinal outcome study of sessile serrated adenomas of the colorectum: an increased risk for subsequent right-sided colorectal carcinoma. Am J Surg Pathol 2010; 34: 927-934
• 13 Schreiner MA, Weiss DG, Lieberman DA. Proximal and large hyperplastic and nondysplastic serrated polyps detected by colonoscopy are associated with neoplasia. Gastroenterology 2010; 139: 1497-1502
• 14 Spring KJ, Zhao ZZ, Karamatic R et al. High prevalence of sessile serrated adenomas with BRAF mutations: a prospective study of patients undergoing colonoscopy. Gastroenterology 2006; 131: 1400-1407
• 15 Lieberman DA, Rex DK, Winawer SJ et al. Guidelines for colonoscopy surveillance after screening and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology 2012; 143: 844-857
• 16 Terdiman JP, McQuaid KR. Surveillance guidelines should be updated to recognize the importance of serrated polyps. Gastroenterology 2010; 139: 1444-1447
• 17 Rex DK, Ahnen DJ, Baron JA et al. Serrated lesions of the colorectum: review and recommendations from an expert panel. Am J Gastroenterol 2012; 107: 1315-1329
• 18 Farris AB, Misdraji J, Srivastava A et al. Sessile serrated adenoma: challenging discrimination from other serrated colonic polyps. Am J Surg Pathol 2008; 32: 30-35
• 19 Sandmeier D, Seelentag W, Bouzourene H. Serrated polyps of the colorectum: is sessile serrated adenoma distinguishable from hyperplastic polyp in a daily practice?. Virchows Arch 2007; 450: 613-618
• 20 Bustamante-Balen M, Bernet L, Cano R et al. Assessing the reproducibility of the microscopic diagnosis of sessile serrated adenoma of the colon. Rev Esp Enferm Dig 2009; 101: 258-264
• 21 Glatz K, Pritt B, Glatz D et al. A multinational, internet-based assessment of observer variability in the diagnosis of serrated colorectal polyps. Am J Clin Pathol 2007; 127: 938-945
• 22 Wong NA, Hunt LP, Novelli MR et al. Observer agreement in the diagnosis of serrated polyps of the large bowel. Histopathology 2009; 55: 63-66
• 23 von Elm E, Altman DG, Egger M et al. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Ann Intern Med 2007; 147: 573-577
• 24 Tadepalli US, Feihel D, Miller KM et al. A morphologic analysis of sessile serrated polyps observed during routine colonoscopy (with video). Gastrointest Endosc 2011; 74: 1360-1368
• 25 Bosman FT. World Health Organization International Agency for Research on Cancer. WHO classification of tumours of the digestive system. 4th. edn. Lyon: International Agency for Research on Cancer; 2010
• 26 Lash RH, Genta RM, Schuler CM. Sessile serrated adenomas: prevalence of dysplasia and carcinoma in 2139 patients. J Clin Pathol 2010; 63: 681-686