BACKGROUND: Tumour infiltrating lymphocytes (TILs) are a key component of the tumour microenvironment. To establish a clinically relevant TILs cut-off for patients with oesophago-gastric (OG) cancer, it is essential to know whether TILs density varies by patient and/or disease characteristics. MATERIALS AND METHODS: (TILs density) by a deep-learning algorithm applied to digitised Haematoxylin/Eosin (H&E)-stained biopsies and resection specimens from 4628 patients from nine phase III trials. 4533 patients with TILs density and matched clinicopathological data were included in the final analyses. Associations between TILs density, disease stage, geographical region (UK versus Asia), sex, age, and treatment were analysed. RESULTS: , p < 0.001). No significant associations were observed with age or sex. CONCLUSIONS: This is the largest study to date evaluating TILs density in OG cancer. TILs density varied with stage and geographical region but not by age or sex. These findings may explain enhanced response to immunotherapy observed in published studies of patients with early-stage disease and highlight the need to account for baseline TILs heterogeneity when interpreting TILs as a possible biomarker in future studies.
Keogh et al. (Tue,) studied this question.