Abstract 4453: Neutrophil-to-lymphocyte ratio associates with intratumoral myeloid predominance and clinical outcomes of pembrolizumab in head and neck squamous cell carcinoma

Neutrophil-to-lymphocyte ratio (NLR) in peripheral blood is an emerging biomarker candidate of immunotherapy in a wide range of cancers. However, little is known about the potential relationships between the tumor immune microenvironment and systemic inflammatory markers including NLR. Here we have explored systemic and tumor-immune microenvironmental characteristics related to treatment outcomes of immune checkpoint inhibition, based on 29 consecutive patients with recurrent/metastatic head and neck squamous cell carcinoma who received pembrolizumab between 2020 and 2021. NLR greater than 4.5 at pretreatment status significantly correlated with short overall survival (OS). Although NLR did not show a significant association with tumor volumes, high NLR exhibited significant correlations with malnutrition status characterized by CONUT (controlling nutritional status), and GNRI (geriatric nutrition risk index). Among the patients whose NLR was greater than 4.5 at pretreatment status, those whose NLR decreased to less than 4.5 at day 21 had a better OS than those whose NLR did not decrease, indicating that longitudinal changes in NLR correlate with prognosis. To investigate association with tumor-immune microenvironment, 14-marker multiplex immunohistochemistry was performed to quantitatively evaluate intratumoral CD8+ T cells, helper T cells, regulatory T cells, B cells, natural killer cells, macrophages, dendritic cells, mast cells, and granulocytes. Notably, NLR at pretreatment status significantly correlated with intratumoral immune cell densities, where high NLR correlated with low lymphoid cells and high tumor associated macrophages in tissue. NLR in peripheral blood significantly correlated with myeloid to lymphoid cell ratios in tissue, suggesting the presence of association between circulating and intratumoral immune complexity profiles. This study highlights that the association between intratumoral myeloid predominance and systemic nutritional and inflammatory status might be a possible factor for resistance to immunotherapy. Understanding immune dynamics in tissue and blood during immunotherapy potentially contributes to the establishment of predictive biomarkers and monitoring for immunotherapy. Citation Format: Hiroki Morimoto, Takahiro Tsujikawa, Aya Miyagawa-Hayashino, Alisa Kimura, Sumiyo Saburi, Junichi Mitsuda, Kanako Yoshimura, Gaku Ohmura, Shigeyuki Mukudai, Hikaru Nagao, Yoichiro Sugiyama, Shibata Saya, Hiroshi Ogi, Eiichi Konishi, Kyoko Itoh, Shigeru Hirano. Neutrophil-to-lymphocyte ratio associates with intratumoral myeloid predominance and clinical outcomes of pembrolizumab in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4453.