title: Diagnosis of T1 colorectal cancer in pedunculated polyps in daily clinical practice: a multicenter study.
abstract: T1 colorectal cancer can be mimicked by pseudo-invasion in pedunculated polyps. British guidelines are currently one of the few which recommend diagnostic confirmation of T1 colorectal cancer by a second pathologist. The aim of this study was to provide insights into the accuracy of histological diagnosis of pedunculated T1 colorectal cancer in daily clinical practice. A sample of 128 cases diagnosed as pedunculated T1 colorectal cancer between 2000 and 2014 from 10 Dutch hospitals was selected for histological review. Firstly, two Dutch expert gastrointestinal pathologists reviewed all hematoxylin-eosin stained slides. In 20 cases the diagnosis T1 colorectal cancer was not confirmed (20/128; 16%). The discordant cases were subsequently discussed with a third Dutch gastrointestinal pathologist and a consensus diagnosis was agreed. The revised diagnoses were pseudo-invasion in 10 cases (10/128; 8%), high-grade dysplasia in 4 cases (4/128; 3%), and equivocal in 6 cases (6/128; 5%). To further validate the consensus diagnosis, the discordant cases were reviewed by an independent expert pathologist from the United Kingdom. A total of 39 cases were reviewed blindly including the 20 cases with a revised diagnosis and 19 control cases where the Dutch expert panel agreed with the original reporting pathologists diagnosis. In 19 of the 20 cases with a revised diagnosis the British pathologist agreed that T1 colorectal cancer could not be confirmed. Additionally, amongst the 19 control cases the British pathologist was unable to confirm T1 colorectal cancer in a further 4 cases and was equivocal in 3 cases. In conclusion, both generalist and expert pathologists experience diagnostic difficulty distinguishing pseudo-invasion and high-grade dysplasia from T1 colorectal cancer. In order to prevent overtreatment, review of the histology of pedunculated T1 colorectal cancers by a second pathologist should be considered with discussion of these cases at a multidisciplinary meeting.
authors.affiliation: Department of Gastroenterology & Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Yara
authors.initials: Y
authors.lastname: Backes
authors.affiliation: Department of Gastroenterology & Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Leon Mg
authors.initials: LM
authors.lastname: Moons
authors.affiliation: Department of Histopathology, University College Hospital, London, UK.
authors.forename: Marco R
authors.initials: MR
authors.lastname: Novelli
authors.affiliation: Department of Gastroenterology & Hepatology, Gelderse Vallei, Ede, The Netherlands.
authors.forename: Jeroen D
authors.initials: JD
authors.lastname: van Bergeijk
authors.affiliation: Department of Gastroenterology & Hepatology, Sint Jansdal, Harderwijk, The Netherlands.
authors.forename: John N
authors.initials: JN
authors.lastname: Groen
authors.affiliation: Department of Gastroenterology & Hepatology, Amphia Hospital, Breda, The Netherlands.
authors.forename: Tom Cj
authors.initials: TC
authors.lastname: Seerden
authors.affiliation: Department of Gastroenterology & Hepatology, Meander Medical Center, Amersfoort, The Netherlands.
authors.forename: Matthijs P
authors.initials: MP
authors.lastname: Schwartz
authors.affiliation: Department of Gastroenterology & Hepatology, Zwolle, The Netherlands.
authors.forename: Wouter H
authors.initials: WH
authors.lastname: de Vos Tot Nederveen Cappel
authors.affiliation: Department of Gastroenterology & Hepatology, Arnhem, The Netherlands.
authors.forename: Bernhard Wm
authors.initials: BW
authors.lastname: Spanier
authors.affiliation: Department of Gastroenterology & Hepatology, Diakonessenhuis, Utrecht, The Netherlands.
authors.forename: Joost Mj
authors.initials: JM
authors.lastname: Geesing
authors.affiliation: Department of Gastroenterology & Hepatology, Flevo Hospital, Almere, The Netherlands.
authors.forename: Koen
authors.initials: K
authors.lastname: Kessels
authors.affiliation: Department of Gastroenterology & Hepatology, Groene Hart Hospital, Gouda, The Netherlands.
authors.forename: Marjon
authors.initials: M
authors.lastname: Kerkhof
authors.affiliation: Department of Gastroenterology & Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.|Department of Gastroenterology and Hematology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Siersema
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: G Johan A
authors.initials: GJ
authors.lastname: Offerhaus
authors.affiliation: Department of Pathology, Diakonessenhuis, Utrecht, The Netherlands.
authors.forename: Anya N
authors.initials: AN
authors.lastname: Milne
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Miangela M
authors.initials: MM
authors.lastname: Lacle
mesh_terms: D000368:Aged; D003106:Colon / Q000473:pathology*; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003111:Colonic Polyps / Q000175:diagnosis* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D012017:Referral and Consultation; D012680:Sensitivity and Specificity