Open Access

ARTICLE

Clinical Value of the Systemic Immune Inflammation Index and PD-L1 Expression in Advanced NSCLC Treated with Pembrolizumab: Real-World Preliminary Study

Hyungkeun Cha¹, Yong Seok Lee², Gui Young Kwon³, Boran Kim⁴, Yeonsook Moon⁵, Lucia Kim⁶, Hae-Seong Nam^1,*

1 Division of Pulmonology, Department of Internal Medicine, Inha University Hospital, Inha University School of Medicine, Incheon, Republic of Korea
2 Department of Obstetrics and Gynecology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
3 Pathology Division, Seoul Clinical Laboratories, Yongin-si, Gyeonggi-do, Republic of Korea
4 Incheon-Namdong Branch, National Health Insurance Corp., Incheon, Republic of Korea
5 Department of Laboratory Medicine, Inha University Hospital, Inha University School of Medicine, Incheon, Republic of Korea
6 Department of Pathology, Inha University Hospital, Inha University School of Medicine, Incheon, Republic of Korea

* Corresponding Author: Hae-Seong Nam. Email:

(This article belongs to the Special Issue: Advances in Cancer Immunotherapy)

Oncology Research 2026, 34(6), 23 https://doi.org/10.32604/or.2026.077514

Received 10 December 2025; Accepted 13 March 2026; Issue published 21 May 2026

Abstract

Objective: Studies on the comprehensive utility of complete blood count-derived inflammatory biomarkers (CBC-IBs) as biomarkers in pembrolizumab-treated advanced non-small-cell lung cancer (NSCLC) are scarce. This study aimed to investigate the clinical relevance of a panel of CBC-IBs as potential predictive biomarkers and assess whether integrating the systemic immune-inflammation index (SII) with programmed death-ligand 1 (PD-L1) expression could overcome the limitations of PD-L1 as a standalone predictive biomarker. Methods: Our real-world preliminary study was conducted on a cohort of patients with advanced NSCLC. Patients who had undergone PD-L1 immunohistochemistry testing at the time of diagnosis, and had completed at least three cycles of pembrolizumab were included. The CBC-IBs analyzed in this study were calculated using absolute cell counts of neutrophils, lymphocytes, monocytes, and platelets. Results: A total of 102 patients were included. Low baseline SII was significantly associated with superior progression-free survival (PFS) (p = 0.031) and overall survival (OS) (p = 0.004). In multivariate analysis, SII emerged as the strongest independent predictor for OS among all evaluated CBC-IBs. Furthermore, patients with a combination of low SII and high PD-L1 expression demonstrated the most favorable survival outcomes. Conclusion: Although further prospective and multicenter studies are needed to validate the generalizability of our findings, the clinical implication is that the use of pretreatment SII and/or PD-L1 expression values may predict therapeutic outcomes and assist in optimizing individualized treatment strategies for patients with advanced NSCLC.

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Supplementary Material

Supplementary Material File

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