Validation of the Consensus Immunoscore for Classification of Colon Cancer


Key Points

  • Results of the Immunoscore assay were highly reproducible among observers and centers.
  • The Immunoscore was a significant independent predictor of recurrence, including among patients with stage II disease. 

As reported in The Lancet by Pagès et al, an international collaboration has validated the consensus Immunoscore for colon cancer as a predictive tool for recurrence of disease.

Study Details

An international consortium of 14 centers in 13 countries, led by the Society for Immunotherapy of Cancer, evaluated the Immunoscore assay in patients with TNM stage I–III colon cancer.

The aim of the study was to assess the prognostic value of total tumor-infiltrating T-cell counts and cytotoxic tumor-infiltrating T-cell counts with the consensus Immunoscore assay. Samples from 2,681 patients were included in the analysis, with patients having been randomized to a training set (n = 700), an internal validation et (n = 636), and an external validation set (n = 1,345). Paraffin sections of tumor and invasive margin from each patient were assessed by immunohistochemistry, with the densities of CD3+ and cytotoxic CD8+ T cells in tumor and invasive margin being quantified by digital pathology. Immunoscores for each patient were derived from the mean of four density percentiles.

The primary endpoint was to determine the prognostic value of the Immunoscore for time to recurrence.

Immunoscore Performance

A high level of reproducibility for the Immunoscore assay was observed among observers and centers (r = 0.97 for colon tumor, r = 0.97 for invasive margin; P < .0001). In the training set, 5-year recurrence was 8% among patients with a high Immunoscore, compared with 19% for an intermediate Immunoscore and 32% for a low Immunoscore (hazard ratio [HR] for high vs low = 0.20, P < .0001). These findings were confirmed in both the internal and external validation sets.

In multivariate analysis, the Immunoscore association with time to recurrence was independent of age, sex, T stage, N stage, microsatellite instability, and other prognostic factors (P < .0001). Among a total of 1,434 patients with stage II cancer, the HR for 5-year risk of recurrence for high vs low Immunoscore was 0.33 (P < .0001), with the association remaining significant on multivariate analysis (P < .0001). In a stratified multivariate analysis of overall survival, the Immunoscore had the greatest contribution to risk (47%) among all clinical parameters, including the American Joint Committee on Cancer/Union for International Cancer Control TNM classification system (28%).

The investigators concluded, “The Immunoscore provides a reliable estimate of the risk of recurrence in patients with colon cancer. These results support the implementation of the consensus Immunoscore as a new component of a TNM-Immune classification of cancer.”

The study was funded by the French National Institute of Health and Medical Research, LabEx Immuno-oncology, Transcan ERAnet Immunoscore European project, Association pour la Recherche contre le Cancer, CARPEM, AP-HP, Institut National du Cancer, Italian Association for Cancer Research, and Society for Immunotherapy of Cancer.

Jerome Galon, PhD, of INSERM, Cordeliers Research Center, Paris, and Franck Pagès, MD, of Hôpital Européen Georges-Pompidou, Paris, are the corresponding authors for The Lancet article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.