Abstract A007: Prognostic significance of complete blood count values and tumor-infiltrating lymphocytes in non-small cell lung cancer patients undergoing immune checkpoint inhibitor therapy

Abstract Background: Lung cancer causes 1.8 million deaths annually and has the highest cancer mortality rate, with 85% of cases being non-small cell lung cancer (NSCLC). Immunotherapy with immune checkpoint inhibitors (ICIs) has shown significant progress, using monoclonal antibodies to modulate crucial immune signals. ICIs are more effective than standard second-line chemotherapy, but reliable prognostic markers are needed. Despite promising results there is a lack of robust prognostic markers that indicate response to ICIs. Aim: The study focused on investigating the prognostic significance of complete blood count (CBC) values and the number of tumor-infiltrating lymphocytes (TILs) for NSCLC patients undergoing ICIs therapy. Methods: A retrospective review was conducted on advanced NSCLC patients treated with ICIs at Barretos Cancer Hospital (Brazil). CBC values were assessed at diagnosis, baseline (before ICI), and after three infusion cycles. TIL percentages were evaluated from diagnostic biopsies stained with hematoxylin and eosin, focusing on mononuclear cells (lymphocytes and plasma cells). Median values were used as cutoff points for CBC and TILs analysis. Demographic data (age, sex, smoking status, histology, staging, PD-L1 status, treatment) were collected. Primary outcomes, overall survival (OS) and progression-free survival (PFS), were assessed via Kaplan-Meier analysis and log-rank test, with Mann-Whitney test used for correlation analysis. Results: The study cohort included 91 patients, with adenocarcinoma being the predominant histological type (57.1%), 54.9% of whom were male, and 63.7% diagnosed at stage IV. Within the cohort, 64.9% had positive PD-L1 status and only 13.2% had never smoked. The study found significant associations between baseline CBC components and clinical outcomes. Lower neutrophil-to-lymphocyte ratios (NLR <3.26) were associated with increased OS (p = 0.014) and PFS (p = 0.024). Conversely, higher lymphocyte-to- monocyte ratios (LMR >2.00) were associated with increased PFS (p = 0.004). Furthermore, LMR counts and the percentage of TILs exhibited a differential distribution between treatment responder and non-responder groups (p = 0.004 and p = 0.050, respectively). Conclusion: Effective management of NSCLC with ICIs remains critical. This study demonstrates that specific CBC components and TILs are valuable prognostic markers in advanced NSCLC patients undergoing ICI therapy. These markers can serve as valuable and cost-effective prognostic biomarkers in guiding treatment strategies. Citation Format: Katiane Tostes, Tauana Christina Dias, Gabriela Karam Rebolho, Leticia Ferro Leal, Lidia Maria Rebolho Batista Arantes. Prognostic significance of complete blood count values and tumor- infiltrating lymphocytes in non-small cell lung cancer patients undergoing immune checkpoint inhibitor therapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A007.