Prognostic value of the Scottish Inflammatory Prognostic Score in advanced NSCLC treated with second-line nivolumab

Purpose: The Scottish Inflammatory Prognostic Score (SIPS), derived from serum albumin and neutrophil count integrates inflammatory and nutritional status. However, its prognostic role in advanced non–small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors remains unclear. Methods: This multicenter, retrospective study included 816 patients with advanced or metastatic NSCLC who received nivolumab following platinum-based chemotherapy between January 2015 and January 2025 at 19 oncology centers in Turkey. The SIPS was calculated at baseline by assigning one point each for albumin < 35 g/L and neutrophil count > 7.5 × 10⁹/L, classifying patients as favorable (0), intermediate (1), or poor (2). Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan–Meier analysis and compared using the log-rank test. Cox regression models were used to identify independent prognostic factors. Results: The median OS decreased across the SIPS groups: 15.0 months (95% CI 12.9–17.1), 8.0 months (95% CI 5.3–10.7), and 5.0 months (95% CI 3.5–6.5) for the favorable, intermediate, and poor groups, respectively (p < 0.001). The median PFS was 7.0, 4.0, and 2.0 months (p < 0.001). In the multivariate analysis, SIPS remained independently associated with both OS (HR = 3.19, 95% CI 1.90–5.35, p < 0.001) and PFS (HR = 3.02, 95% CI 1.89–4.84, p < 0.001). Conclusions: Baseline SIPS is a simple, cost-effective, and independent prognostic biomarker in nivolumab-treated NSCLC. Prospective studies are needed to validate these findings and evaluate its integration with other markers to improve clinical risk stratification and may be useful for prognostic assessment.