Radiomic Signature for CD8 Cell Tumor Infiltration and Response to Treatment

Key Points

  • A radiomic signature was developed that distinguished between tumors with high vs low CD8 infiltration.
  • Tumors with high baseline radiomic signature scores were associated with better outcome of PD-1/PD-L1 inhibitor treatment.

In a study reported in The Lancet Oncology, Sun et al developed a radiomic signature of infiltrating CD8 cells that could identify tumor immune phenotype and help predict outcome of programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) inhibitor treatment.

Study Details

The study involved several cohorts of patients with advanced solid tumors. A radiomic signature was developed using contrast enhanced computed tomography (CT) images and RNA sequencing genomic data based on CD8B gene for individual tumors, with estimates of abundance of CD8 cells being aligned with CT images. The final radiomic signature for CD8 cells included eight variables.

Validation and Performance of Radiomic Signature

The radiomic signature was shown to be correlated with the gene expression signature of CD8 cells in a cohort (n = 119) from The Cancer Genome Atlas database (area under the curve [AUC]= 0.67, P = .0019). In a Gustave Roussy cohort (n = 100) of patients with extreme tumor immune phenotypes, consisting of immune-inflamed (dense CD8 cell infiltration) or immune-desert (low CD8 cell infiltration) phenotypes irrespective of treatment, the radiomic signature distinguished the former from the latter (AUC = 0.76, P < .0001).

In a Gustave Roussy dataset (n = 137) of patients receiving PD-1/PD-L1 inhibitor treatment in phase I trials, high baseline radiomic score (above median) was associated with greater likelihood of objective response at 3 months vs progressive disease or stable disease (P = .049), objective response vs progressive disease or stable disease (P = .025), and stable disease vs progressive disease at 6 months (P = .013). High baseline radiomic score was associated with improved median overall survival in univariate analysis (24.3 vs 11.5 months, hazard ratio [HR] = 0.58, P = .0081) and multivariate analysis (HR = 0.52, P = .0022).

The investigators concluded, “The radiomic signature of CD8 cells was validated in three independent cohorts. This imaging predictor provided a promising way to predict the immune phenotype of tumours and to infer clinical outcomes for patients with cancer who had been treated with anti–PD-1/PD-L1. Our imaging biomarker could be useful in estimating CD8 cell count and predicting clinical outcomes of patients treated with immunotherapy, when validated by further prospective randomi[z]ed trials.”

The study was funded by Fondation pour la Recherche Médicale and French Society of Radiation Oncology.

Eric Deutsch, MD, of the Department of Radiation Oncology, Gustave Roussy Cancer Campus, is the corresponding author for The Lancet Oncology 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®.


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