Standardized evaluation of tumor-infiltrating lymphocytes in breast cancer: Results of the ring studies of the international immuno-oncology biomarker working group

Carsten Denkert, Stephan Wienert, Audrey Poterie, Sibylle Loibl, Jan Budczies, Sunil Badve, Zsuzsanna Bago-Horvath, Anita Bane, Shahinaz Bedri, Jane Brock, Ewa Chmielik, Matthias Christgen, Cecile Colpaert, Sandra Demaria, Gert Van Den Eynden, Giuseppe Floris, Stephen B. Fox, Dongxia Gao, Barbara Ingold Heppner, S. Rim KimZuzana Kos, Hans H. Kreipe, Sunil R. Lakhani, Frederique Penault-Llorca, Giancarlo Pruneri, Nina Radosevic-Robin, David L. Rimm, Stuart J. Schnitt, Bruno V. Sinn, Peter Sinn, Nicolas Sirtaine, Sandra A. O'Toole, Giuseppe Viale, Koen Van De Vijver, Roland De Wind, Gunter Von Minckwitz, Frederick Klauschen, Michael Untch, Peter A. Fasching, Toralf Reimer, Karen Willard-Gallo, Stefan Michiels, Sherene Loi, Roberto Salgado

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Abstract

Multiple independent studies have shown that tumor-infiltrating lymphocytes (TIL) are prognostic in breast cancer with potential relevance for response to immune-checkpoint inhibitor therapy. Although many groups are currently evaluating TIL, there is no standardized system for diagnostic applications. This study reports the results of two ring studies investigating TIL conducted by the International Working Group on Immuno-oncology Biomarkers. The study aim was to determine the intraclass correlation coefficient (ICC) for evaluation of TIL by different pathologists. A total of 120 slides were evaluated by a large group of pathologists with a web-based system in ring study 1 and a more advanced software-system in ring study 2 that included an integrated feedback with standardized reference images. The predefined aim for successful ring studies 1 and 2 was an ICC above 0.7 (lower limit of 95% confidence interval (CI)). In ring study 1 the prespecified endpoint was not reached (ICC: 0.70; 95% CI: 0.62-0.78). On the basis of an analysis of sources of variation, we developed a more advanced digital image evaluation system for ring study 2, which improved the ICC to 0.89 (95% CI: 0.85-0.92). The Fleiss' kappa value for <60 vs ≥60% TIL improved from 0.45 (ring study 1) to 0.63 in RS2 and the mean concordance improved from 88 to 92%. This large international standardization project shows that reproducible evaluation of TIL is feasible in breast cancer. This opens the way for standardized reporting of tumor immunological parameters in clinical studies and diagnostic practice. The software-guided image evaluation approach used in ring study 2 may be of value as a tool for evaluation of TIL in clinical trials and diagnostic practice. The experience gained from this approach might be applicable to the standardization of other diagnostic parameters in histopathology.

Original languageEnglish
Pages (from-to)1155-1164
Number of pages10
JournalModern Pathology
Volume29
Issue number10
DOIs
Publication statusPublished - 1 Oct 2016

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ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Cite this

Denkert, C., Wienert, S., Poterie, A., Loibl, S., Budczies, J., Badve, S., Bago-Horvath, Z., Bane, A., Bedri, S., Brock, J., Chmielik, E., Christgen, M., Colpaert, C., Demaria, S., Van Den Eynden, G., Floris, G., Fox, S. B., Gao, D., Ingold Heppner, B., ... Salgado, R. (2016). Standardized evaluation of tumor-infiltrating lymphocytes in breast cancer: Results of the ring studies of the international immuno-oncology biomarker working group. Modern Pathology, 29(10), 1155-1164. https://doi.org/10.1038/modpathol.2016.109