Systemic Immune-inflammation Index is the Best Prognostic Factor in Patients with Advanced Stage Adenocarcinoma of the Lung Treated with Pemetrexed

Objective: To evaluate the prognostic role of systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) in patients who received platin-pemetrexed combination therapy and/or maintenance pemetrexed therapy.

Study Design: Observational study.

Place And Duration Of Study: Department of Medical Oncology, HSU Dr. Abdurrahman Yurtaslan Oncology, Training and Research Hospital, Turkey, between January 2010 and March 2020.

Methodology: Data of patients with metastatic adenocarcinoma of lung, who underwent platin-pemetrexed combination therapy and/or maintenance pemetrexed therapy retrospectively, were evaluated. Patient characteristics and disease parameters were recorded. Moreover, NLR, PLR, and SII were calculated. Survival analysis with the Kaplan-Meier and Log-rank test was performed. Cox regression analysis was used to determine independent prognostic factors of overall survivall (OS) and progression-free survival (PFS).

Results: In the univariate analyses, NLR-low group and SII-low group had significantly longer PFS compared to NLR-high and SII-high groups (10 months vs. 8 months, p=0.018, and 13 months vs. 8 months, p<0.001, respectively). The significant differences were seen between SII-low and SII-high groups for OS (24 months vs. 13 months, p=0.001). In multivariate analyses, response to treatment and low-SII were independent prognostic factors for PFS (HR: 0.25, p<0.001, and HR: 0.47, p=0.002, respectively) and OS (HR: 2.09, p=0.001, and HR: 2.05, p=0.001, respectively).   Conclusion: SII is the most powerful of the three studied inflammatory indices, which could independently predict overall and progression-free survival. Key Words: Systemic immune-inflammation index, Neutrophil-to-lymphocyte ratio, Platelet-to-lymphocyte ratio, Adenocarcinoma, Lung cancer, Pemetrexed.