Identification of areas of grading difficulties in prostate cancer and comparison with artificial intelligence assisted grading.

Journal: Virchows Archiv : an international journal of pathology
Published Date: Jun 15, 2020

Abstract

The International Society of Urological Pathology (ISUP) hosts a reference image database supervised by experts with the purpose of establishing an international standard in prostate cancer grading. Here, we aimed to identify areas of grading difficulties and compare the results with those obtained from an artificial intelligence system trained in grading. In a series of 87 needle biopsies of cancers selected to include problematic cases, experts failed to reach a 2/3 consensus in 41.4% (36/87). Among consensus and non-consensus cases, the weighted kappa was 0.77 (range 0.68-0.84) and 0.50 (range 0.40-0.57), respectively. Among the non-consensus cases, four main causes of disagreement were identified: the distinction between Gleason score 3 + 3 with tangential cutting artifacts vs. Gleason score 3 + 4 with poorly formed or fused glands (13 cases), Gleason score 3 + 4 vs. 4 + 3 (7 cases), Gleason score 4 + 3 vs. 4 + 4 (8 cases) and the identification of a small component of Gleason pattern 5 (6 cases). The AI system obtained a weighted kappa value of 0.53 among the non-consensus cases, placing it as the observer with the sixth best reproducibility out of a total of 24. AI may serve as a decision support and decrease inter-observer variability by its ability to make consistent decisions. The grading of these cancer patterns that best predicts outcome and guides treatment warrants further clinical and genetic studies. Results of such investigations should be used to improve calibration of AI systems.

Authors

  • Lars Egevad
    Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.
  • Daniela Swanberg
    Department of Oncology-Pathology, Karolinska Institutet|, Karolinska University Hospital, Radiumhemmet P1:02, 171 76, Stockholm, Sweden.
  • Brett Delahunt
    Department of Pathology and Molecular Medicine, Wellington School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand.
  • Peter Ström
    Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
  • Kimmo Kartasalo
    BioMediTech and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.
  • Henrik Olsson
    Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
  • Dan M Berney
    Barts Cancer Institute, Queen Mary University of London, London, UK.
  • David G Bostwick
    Bostwick Laboratories, Orlando, FL, USA.
  • Andrew J Evans
    Laboratory Medicine Program, University Health Network, Toronto General Hospital, Toronto, ON, Canada.
  • Peter A Humphrey
    Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
  • Kenneth A Iczkowski
    Department of Pathology, Medical College of Wisconsin, Milwaukee, WI, USA.
  • James G Kench
    Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital and Central Clinical School, University of Sydney, Sydney, NSW, Australia.
  • Glen Kristiansen
    Institute of Pathology, University Hospital Bonn, Bonn, Germany.
  • Katia R M Leite
    Department of Urology, Laboratory of Medical Research, University of São Paulo Medical School, São Paulo, Brazil.
  • Jesse K McKenney
    Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, OH, USA.
  • Jon Oxley
    Department of Cellular Pathology, Southmead Hospital, Bristol, UK.
  • Chin-Chen Pan
    Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan.
  • Hemamali Samaratunga
    Aquesta Uropathology and University of Queensland, Brisbane, QLD, Australia.
  • John R Srigley
    Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
  • Hiroyuki Takahashi
    Department of Pathology, Jikei University School of Medicine, Tokyo, Japan.
  • Toyonori Tsuzuki
    Department of Surgical Pathology, Aichi Medical University Hospital, Aichi 480-1195, Japan. tsuzuki@aichi-med-u.ac.jp.
  • Theo van der Kwast
    Laboratory Medicine Program, University Health Network, Toronto, ON, Canada.
  • Murali Varma
    Department of Cellular Pathology, University Hospital of Wales, Cardiff, UK.
  • Ming Zhou
    Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA.
  • Mark Clements
    Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
  • Martin Eklund
    Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. Electronic address: martin.eklund@ki.se.

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