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Unravelling interobserver variability in gastrointestinal glandular neoplasia: a contemporary study of US and Korean pathologists
  1. Richard R Pacheco1,
  2. Hyunki Kim2,
  3. Won-Tak Choi3,
  4. Myeong-Cherl Kook4,
  5. Mee-Yon Cho5,
  6. Dipti M Karamchandani6,
  7. Michael J Lee7,
  8. Baek-Hui Kim8,
  9. Sung-Hak Lee9,
  10. Zhaohai Yang10,
  11. Jihun Kim11,
  12. Stephen M Lagana7,
  13. Hwajeong Lee1
  1. 1Pathology and Laboratory Medicine, Albany Medical Center, Albany, New York, USA
  2. 2Pathology, Yonsei University College of Medicine, Seodaemun-gu, Seoul, Korea
  3. 3Pathology, University of California, San Francisco, California, USA
  4. 4Pathology/Center for Gastric Cancer, National Cancer Center, Goyang, Korea
  5. 5Department of Pathology, Yonsei University College of Medicine, Wonju, Gangwon-do, Korea
  6. 6Department of Pathology, Division of Anatomic Pathology, UT Southwestern Medical Center, Dallas, Texas, USA
  7. 7Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
  8. 8Pathology, Korea University Guro Hospital, Seoul, Korea
  9. 9Hospital Pathology, The Catholic University of Korea College of Medicine, Seoul, Korea
  10. 10Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
  11. 11Department of Pathology, University of Ulsan College of Medicine, Seoul, Korea
  1. Correspondence to Dr Hwajeong Lee, Albany Medical Center, Albany, NY 12208, USA; LeeH5{at}


Aims Interobserver variability in the assessment of gastric neoplasia biopsies between most Western and Eastern (predominantly represented by Japanese in the literature) pathologists has been documented. It is unknown if such variability exists between the US and Korean pathologists in the current era.

Methods Ten gastrointestinal (GI) pathologists from the USA (n=5) and South Korea (n=5) evaluated 100 scanned images of gastric (n=50) and colorectal (n=50) neoplasia biopsies and answered multiple questionnaires. Consensus was defined as the answer chosen by the majority. Cohen’s (κc) and Fleiss’ kappa (κf) values were calculated between the consensus of the two groups and among the raters, respectively.

Results Both groups reached a consensus in the majority of cases (74%–100%) with slight to perfect intergroup (κc=0.049–1.000) and no to substantial intragroup (κf=−0.083 to 0.660) agreements. For gastric neoplasia, Korean pathologists relied heavily on cytoarchitectural atypia, whereas the US pathologists focused on stromal invasion when diagnosing adenocarcinoma. For colorectal neoplasia, the Korean pathologists identified concurrent intramucosal carcinoma when diagnosing invasive adenocarcinoma, while the presence of desmoplasia was a prerequisite for the diagnosis of invasive adenocarcinoma for the US pathologists.

Conclusions For GI neoplasia biopsy interpretation, the diagnostic approach of Korean pathologists is similar to that of Eastern/Japanese pathologists. Consensus outperformed kappa statistics in capturing the magnitude of inter-rater and intergroup reliability, highlighting the potential benefit of consensus meetings to decrease the gap between Western and Eastern diagnostic approaches.

  • gastrointestinal neoplasms
  • pathology, surgical
  • stomach neoplasms
  • colorectal neoplasms

Data availability statement

All data relevant to the study are included in the article.

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Data availability statement

All data relevant to the study are included in the article.

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  • Handling editor Deepa Patil.

  • Twitter @RRPacheco_MD, @HwajeongL

  • Contributors RRP analysed the data and wrote the manuscript. HK designed and performed the study and critically revised the manuscript. W-TC, M-CK, M-YC, DMK, MJL, B-HK, S-HL, ZY, JK and SML performed the study and critically revised the manuscript. HL (guarantor) conceptualised and designed the study, performed the study, analysed the data and critically revised the manuscript. All authors read and approved the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.