Compactness measures of tumor infiltrating lymphocytes in lung adenocarcinomas are associated with overall patient survival and immune scores

Lung adenocarcinoma (LUAD), the most common type of lung cancer, has an average 5-year survival rate of 15%. In LUAD, interaction between tumor and immune cells has been shown to be highly associated with the likelihood of disease progression and metastases. We have previously demonstrated the association between spatial architecture and arrangement of tumor-infiltrating lymphocytes (TILs) with likelihood of recurrence in early stage NSCLC. Recently, gene set enrichment analysis-derived immune scores have been found to be prognostic of outcome. However, this requires transcriptomics techniques as a precursor, which involves mechanical disruption of cells and tissues. In this work (N = 170), we extracted graph-based histomorphometric features on segmented nuclei from digitized H&E biopsy images and then performed principal component analysis (PCA) to select the most representative tiles from each patient. We then identified TILs and quantitative histomorphometric attributes of different nuclei groups (all-nuclei, TILs, non-TILs) prognostic of overall patient survival (OS) and further investigated their associations with immune scores and biological pathways implicated immune response using gene-set enrichment analysis (GSEA). We found TIL-compactness (a set of TIL density features) derived risk scores were prognostic of OS (Hazard Ratio (HR) = 3.26, p = 0.012, C-index = 0.634). The median immune score (IS) in the cohort was used as a threshold to divide the cases into low and high IS expression groups. The TIL compactness measures prognostic of OS were also statistically significantly correlated with the IS and biological pathways related to immune response (Immune System Process, Immune Response, Adaptive Immune Response, and Humoral Immune Response Mediated by Circulating Immunoglobulin).