Assessment of pathologic interpretation of colorectal polyps by general pathologists in community practice Bernard DENIS, Carol PETERS, Catherine CHAPELAIN, Isabelle KLEINCLAUS, Anne FRICKER, Richard WILD, Bernard AUGE, Denis CHATELAIN, Jean François FLEJOU Association pour le dépistage du cancer colorectal dans le Haut-Rhin (ADECA 68) Colmar, France

B. Denis - DDW 2007 – Washington DC background l The assessment of type and dysplasia of colorectal polyps is poorly reproducible in clinical practice Demers RY 1990, Jensen P 1995, Rex DK 1999, Yoon H 2002, Costantini M 2003, Komuta K 2004

B. Denis - DDW 2007 – Washington DC background l population-based CRC screening program with guaiac based FOBT l Haut-Rhin: u 1 of 23 pilot areas u residents aged y l May 2006: 2560 polyps / 1274 people

B. Denis - DDW 2007 – Washington DC background P<0.001 Rate of adenomas with >20% villous elements. Goal: <10% Recommendations U.S. multi-society task force on CRC. Am J Gastroenterol 2002

B. Denis - DDW 2007 – Washington DC aim to assess l performances of community pathologists in the interpretation of colorectal polyps l clinical impact on a population-based FOBT CRC screening program

B. Denis - DDW 2007 – Washington DC methods l screening program 2560 polyps = whole cohort slides / 14 community pathologists (P1) l study u sample of 300 polyps (11.7%) all serrated adenomas (n = 71) all in situ (n = 77) and T1 carcinomas (n = 39) other polyps selected at random (n = 114) u review sslides / 2 expert GI academic pathologists (P2) spathology reports of malignant polyps

B. Denis - DDW 2007 – Washington DC results – study population histology sample P2 n = 292 n (%) adenomatous polyps192 (65.8) tubular60 (20.5) tubulovillous122 (41.8) villous10 (3.4) serrated polyps98 (33.6) hyperplastic77 (26.4) serrated ad. + SSA14 (4.8)

B. Denis - DDW 2007 – Washington DC results – study population histology sample P2 n = 292 n (%) whole cohort P1 n = 2368 n (%) p adenomatous polyps192 (65.8)1833 (77.4)< tubular60 (20.5)1331 (56.2)< tubulovillous122 (41.8)456 (19.3)< villous10 (3.4)46 (1.9)NS serrated polyps98 (33.6)468 (19.8)< hyperplastic77 (26.4)393 (16.6)< serrated ad. + SSA14 (4.8)75 (3.2)NS

B. Denis - DDW 2007 – Washington DC results – community pathologists performances histology agreement 300 polyps (%) sensitivity 300 polyps (%) specificity 300 polyps (%) adenomatous polyps serrated polyps

B. Denis - DDW 2007 – Washington DC histology agreement 300 polyps (%) sensitivity 300 polyps (%) specificity 300 polyps (%) >20% villous elements hyperplastic serrated adenomas results – community pathologists performances

B. Denis - DDW 2007 – Washington DC clinical impact l 2 questions to the pathologist u is the polyp malignant? if yes, is surgery needed? u is colonoscopic surveillance needed? if yes, when? no 5 y3 y yes

B. Denis - DDW 2007 – Washington DC results – clinical impact 261 benign polyps ≥ 10 mm< 10 mm disagreement with impact6.1%58.4% over surveillance6.1%54.0% under surveillance0%4.4%

B. Denis - DDW 2007 – Washington DC results – clinical impact 261 benign polyps ≥ 10 mm< 10 mm disagreement with impact6.1%58.4% over surveillance6.1%54.0% under surveillance0%4.4%

B. Denis - DDW 2007 – Washington DC results – clinical impact 36 malignant polyps n (%) disagreement with impact11 (25.6) over treatment7 (16.3) under treatment4 (9.3)

B. Denis - DDW 2007 – Washington DC Bayes formulae PPV = Se x P NPV = Sp x (1 - P) Se x P + (1 - P) x (1 - Sp) Sp x (1 - P) + P x (1 – Se) PPV whole cohort NPV whole cohort T1 carcinoma34.9%99.8% results – community pathologists performances

B. Denis - DDW 2007 – Washington DC results – overall clinical impact whole cohort agreement45.2% disagreement without impact27.5% disagreement with impact27.2%

B. Denis - DDW 2007 – Washington DC results – pathology reports of malignant polyps

B. Denis - DDW 2007 – Washington DC conclusion l poor inter-observer agreement in the pathologic interpretation of colorectal polyps by community pathologists l in the real world, impact on clinical management: 1/4 of cases l frequent lack of adequate characterization of malignant polyps

B. Denis - DDW 2007 – Washington DC future l benign polyps u need for a clarification (simplification) of the nomenclature, especially for serrated polyps u surveillance interval for polyps ≥ 10 mm should be 3 years whatever the pathology report may be l malignant polyps u slides should be reviewed by expert pathologists u need for a standardized pathology report

B. Denis - DDW 2007 – Washington DC standardized pathology report for malignant polyps degree of differentiation: …….. angiolymphatic invasion: ……… resection margin status: ……… T stage: ……….

B. Denis - DDW 2007 – Washington DC acknowledgements l Bernard Auge l Catherine Chapelain l Anne Fricker l Sylvette Itten l Isabelle Kleinclaus l Sylvie Krzisch l Denis Laedlein l Carol Peters l Martine Prevot l Sylvie Rozan l Pierre Straub l Sylvie Thiebault l Marie Claire Tortel l Richard Wild