title: Sessile serrated polyps at screening colonoscopy: have they been under diagnosed?
abstract: OBJECTIVE
  The sessile serrated adenoma/polyp (SSA/P) is increasingly recognized as an important precursor to colorectal cancer (CRC) and may contribute to proximal postcolonoscopy CRCs. Hyperplastic polyps (HPs) generally follow a more benign course than do SSA/Ps, but they have a similar histologic appearance. Our aims were to identify patient and polyp factors associated with reclassification of HPs as SSA/Ps during a central pathology review and to characterize and compare their subsequent clinical management with other polyps.
  
  
  METHODS
  From 2003 to 2008, we prospectively enrolled asymptomatic persons aged 50-74 years in a study of screening colonoscopy. Because criteria for SSA/P diagnosis evolved over our study period, we initiated a second review of all HPs >5 mm in size in 2011, with reclassification of polyps if indicated. Rates of subsequent colonoscopies, polypectomies, and CRCs were identified.
  
  
  RESULTS
  We enrolled 2,527 persons who underwent colonoscopy in whom 111 had HPs >5 mm. Thirty-two of the 111 participants (28.8%) with HPs >5 mm had their polyps reclassified as SSA/Ps. There were no significant differences in patient characteristics between those with reclassified SSA/Ps and those who had HPs >5 mm. SSA/Ps were more likely to be proximal (P<0.001) and larger (P<0.007) than the HPs. In all, 48.3% of those with high-risk adenomas received appropriate follow-up compared with 26.1% of those with high-risk SSA/Ps.
  
  
  CONCLUSIONS
  Almost 1/3 of recently diagnosed HPs >5 mm were reclassified as SSA/Ps. Patients previously diagnosed with larger HPs in the proximal colon may benefit from a pathologic review to ensure appropriate diagnosis and follow-up.
authors.affiliation: 1] Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada [2] Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Jill
authors.initials: J
authors.lastname: Tinmouth
authors.affiliation: 1] Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Pauline
authors.initials: P
authors.lastname: Henry
authors.affiliation: 1] Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Eugene
authors.initials: E
authors.lastname: Hsieh
authors.affiliation: 1] Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada [2] Department of Surgery, University of Toronto, Toronto, Ontario, Canada [3] Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Nancy N
authors.initials: NN
authors.lastname: Baxter
authors.affiliation: Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hilsden
authors.affiliation: 1] Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada [2] Alberta Health Services Cancer Care, Calgary, Alberta, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Elizabeth McGregor
authors.affiliation: 1] Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada [2] Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada [3] Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada [4] Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada [5] Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: Paszat
authors.affiliation: Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Arlinda
authors.initials: A
authors.lastname: Ruco
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
authors.forename: Refik
authors.initials: R
authors.lastname: Saskin
authors.affiliation: 1] Calgary Laboratory Services, Calgary, Alberta, Canada [2] Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Schell
authors.affiliation: 1] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada [2] Department of Pathology, UHN Toronto General Hospital, Toronto, Ontario, Canada.
authors.forename: Emina E
authors.initials: EE
authors.lastname: Torlakovic
authors.affiliation: 1] Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada [2] Cancer Care Ontario, Toronto, Ontario, Canada [3] Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada [4] Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada [5] Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Rabeneck
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery; D000368:Aged; D003111:Colonic Polyps / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011230:Precancerous Conditions / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery; D011446:Prospective Studies