Validation of the Scottish Inflammatory Prognostic Score (SIPS) in NSCLC Patients Treated with First-Line Pembrolizumab.

Background: The Scottish Inflammatory Prognostic Score (SIPS), combining albumin (≥/<35 g/L) and neutrophil count (≤/>7.5 × 10/L), has been identified as a prognostic biomarker for patients with non-small cell lung cancer (NSCLC) undergoing treatment with pembrolizumab monotherapy. We sought to validate this biomarker of systemic inflammation in an external cohort.

Methods: Patients treated with first-line pembrolizumab for advanced NSCLC with programmed death-ligand 1 (PD-L1) expression ≥ 50% at an English cancer centre were identified. Pre-treatment clinicopathological characteristics and the SIPS were recorded. The relationship between these and progression-free survival (PFS) and overall survival (OS) was examined.

Results: Among 257 patients evaluated, 56% ( = 144) were classified as SIPS 0, 36% ( = 93) as SIPS 1, and 8% ( = 20) as SIPS 2. Factors such as age, performance status (PS) and brain metastases presence were significantly correlated with SIPS categories. Multivariate analysis revealed that both SIPS and PD-L1 status were independently associated with PFS and OS. The combination of SIPS with either PS or PD-L1 expression enhanced the ability to detect patients with the most favourable or poorest survival.

Conclusions: Our study confirms the prognostic significance of the SIPS in patients with advanced NSCLC treated with pembrolizumab in the context of high PD-L1 expression. SIPS offers a straightforward, clinically applicable approach to patient stratification, potentially guiding therapeutic decisions and enhancing outcomes in advanced NSCLC. Future research should focus on validating these findings in prospective studies and exploring the integration of SIPS into clinical practice, alongside other prognostic markers, to optimize treatment strategies.