Original article| Volume 56, ISSUE 3, P209-214, March 2003

Interobserver agreement in the histologic diagnosis of colorectal polyps

the experience of the multicenter adenoma colorectal study (SMAC)


      Current clinical practice guidelines for patients with colorectal polyps are mainly based on the histologic characteristics of their lesions. However, interobserver variability in the assessment of specific polyp characteristics was evaluated in very few studies. The purpose of this study was to evaluate the interobserver agreement of four pathologists in the diagnosis of histologic type of colorectal polyps and in the degree of dysplasia and of infiltrating carcinoma in adenomas. A stratified random sample of 100 polyps was obtained from the 4,889 polyps resected within the Multicentre Adenoma Colorectal Study (SMAC), and the slides were blindly reviewed by the four pathologists. Agreement was analyzed using kappa statistics. A median kappa of 0.89 (range 0.79–1.0) was estimated for the interobserver agreement for the diagnosis of hyperplastic polyp vs. adenoma. The agreement in the diagnosis of tubular, tubulovillous, and villous type, was given by median kappa values of 0.50, 0.15, and 0.36, respectively. The median kappa for the diagnosis of infiltrating carcinoma was 0.78 (range 0.73–0.84). Agreement on diagnosis of adenoma histologic subtypes, degrees of dysplasia, or infiltrating carcinoma in adenoma was moderate. A simpler classifications might help to better identify patients at different risk of colorectal cancer.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Clinical Epidemiology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Eide T.J.
        • Stalsberg H.
        Polyps of the large intestine in Northern Norway.
        Cancer. 1978; 42: 2839-2845
        • Clark J.C.
        • Collan Y.
        • Eide T.J.
        • Esteve J.
        • Ewens S.
        • Gibbs N.M.
        • et al.
        Prevalence of polyps in an autopsy series from areas with varying incidence of large bowel cancer.
        Int J Cancer. 1985; 36: 179-186
        • Coode P.E.
        • Chan K.W.
        • Chan Y.T.
        Polyps and diverticula of the large intestine.
        Gut. 1985; 26: 1045-1053
        • Johnson D.A.
        • Guiney M.S.
        • Volpe R.J.
        • Jones D.M.
        • Van Ness M.M.
        • Chobanian S.J.
        • et al.
        A prospective study of the prevalence of colonic neoplasms in asymptomatic patients with an age-related risk.
        Am J Gastroenterol. 1990; 85: 969-975
        • Rex D.K.
        • Lehman G.A.
        • Hawes R.H.
        • Ulbright T.M.
        • Smith J.J.
        Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests.
        Gastroenterology. 1991; 100: 64-70
        • DiSario J.A.
        • Foutch P.G.
        • Mai H.D.
        Prevalence and malignant potential of colorectal polyps in asymptomatic average-risk men.
        Am J Gastroenterol. 1991; 86: 941-949
        • Lieberman D.A.
        • Weiss D.G.
        • Bond J.H.
        • Ahnen D.J.
        • Garewal H.
        • Chejfec G.
        • for the Veterans Affairs Cooperative Study Group 380
        Use of colonoscopy to screen asymptomatic adults for colorectal cancer.
        N Engl J Med. 2000; 343: 162-168
        • Muto T.
        • Bassey H.J.R.
        • Morson B.C.
        The evolution of cancer of the colon and rectum.
        Cancer. 1975; 36: 2251-2270
        • Fenoglio C.M.
        • Pascal R.R.
        Colorectal adenomas and cancer.
        Cancer. 1982; 50: 2601-2608
        • Brown L.J.
        • Smeeton N.C.
        • Dixon M.F.
        Assessment of dysplasia in colorectal adenomas.
        J Clin Pathol. 1985; 38: 174-179
        • Fenger C.
        • Bak M.
        • Kronborg O.
        • Svanholm H.
        Observer reproducibility in grading dysplasia in colorectal adenomas.
        J Clin Pathol. 1990; 43: 320-324
        • Demers R.Y.
        • Neale A.V.
        • Budev H.
        • Schade W.J.
        Pathologist agreement in the interpretation of colorectal polyps.
        Am J Gastroenterol. 1990; 85: 417-421
        • Jensen P.
        • Krogsgaard M.R.
        • Christiansen J.
        • Braendstrup O.
        • Johansen A.
        • Olsen J.
        Observer variability in the assessment of type and dysplasia of colorectal adenomas, analyzed using kappa statistics.
        Dis Colon Rectum. 1995; 38: 195-198
        • Rex D.K.
        • Alikhan M.
        • Cummings O.
        • Ulbright T.M.
        Accuracy of pathologic interpretation of colorectal polyps by general pathologists in community practice.
        Gastrointest Endosc. 1999; 50: 468-474
        • Cross S.S.
        • Betmouni S.
        • Burton J.L.
        • Dube A.K.
        • Feeley K.M.
        • Holbrook M.R.
        • et al.
        What levels of agreement can be expected between histopathologists assigning cases to discrete nominal categories? A study of the diagnosis of hyperplastic and adenomatous colorectal polyps.
        Mod Pathol. 2000; 13: 941-944
        • The Multicenter Study of Colorectal Adenomas
        • SMAC) Workgroup
        A multicenter study of colorectal adenomas. Rationale, objectives, methods and characteristics of the study cohort.
        Tumori. 1995; 81: 157-163
      1. Morson BC, Sobin LH. Histologic typing of intestinal tumours. In: International histological classification of tumors. Vol. 15. Geneva: World Health Organization; 1976.

        • Bond J.H.
        Polyp guideline.
        Am J Gastroenterol. 2000; 95: 3053-3063
        • Fleiss J.L.
        Statistical methods for rates and proportions. 2nd ed. Wiley;, New York1981 (p. 217.)
        • Imperiale T.F.
        • Wagner D.R.
        • Lin C.Y.
        • Larkin G.N.
        • Rogge J.D.
        • Ransohoff D.F.
        Risk of advanced proximal neoplasms in asymptomatic adults according to the distal colorectal finding.
        N Engl J Med. 2000; 23: 169-174
        • Atkin W.S.
        • Morson B.C.
        • Cuzick J.
        Long Term risk of colorectal cancer after excision of rectosigmoid adenomas.
        N Engl J Med. 1992; 326: 658-662
        • Cranley J.P.
        • Petras R.E.
        • Carey W.D.
        • Paradis K.
        • Sivak M.V.
        When is endoscopic polypectomy adequate therapy for colonic polyps containing invasive carcinoma?.
        Gastroenterology. 1986; 91: 419-427
        • Coverlizza S.
        • Risio M.
        • Ferrari A.
        • Fenoglio-Preiser C.M.
        • Rossini F.P.
        Colorectal adenomas containing invasive carcinoma. Pathologic assessment of lymph node metastatic potential.
        Cancer. 1989; 64: 1937-1947
        • Atkin W.S.
        • Edwards R.
        • Wardle J.
        • Northover J.M.
        • Sutton S.
        • Hart A.R.
        • Williams C.B.
        • Cuzick J.
        Design of a multicentre randomised trial to evaluate flexible sigmoidoscopy in colorectal cancer screening.
        J Med Screen. 2001; 8: 137-144
        • Brennan P.
        • Silman A.
        Statistical methods for assessing observer variability in clinical measures.
        BMJ. 1992; 304: 1491-1494
        • Byrt T.
        • Bishop J.
        • Carlin J.B.
        Bias, prevalence and kappa.
        J Clin Epidemiol. 1993; 46: 423-429
        • Schlemper R.J.
        • Riddell R.H.
        • Kato Y.
        • Borchard F.
        • Cooper H.S.
        • Dawsey S.M.
        • et al.
        The Vienna Classification of gastrointestinal epithelial neoplasia.
        Gut. 2000; 47: 251-255
        • Winawer S.J.
        • Zauber A.G.
        • O'Brien M.J.
        • Gottlieb L.S.
        • Sternberg S.S.
        • Stewart E.T.
        • et al.
        The National Polyp Study. Design, methods, and characteristics of patients with newly diagnosed polyps.
        The National Polyp Study Workgroup. Cancer. 1992; 70: 1236-1245