Supplementary Material for: The Glasgow Prognostic Score as a Predictor of Survival After Chemoradiotherapy for Limited-Disease Small Cell Lung Cancer

Introduction: Established biomarkers for predicting chemoradiotherapy efficacy for limited-disease small cell lung cancer (LD-SCLC) are lacking. The inflammation-based Glasgow Prognostic Score (GPS), comprising serum C-reactive protein (CRP) and albumin levels, can predict survival in advanced cancer. This study investigated whether metabolic and inflammatory markers, including the GPS, can predict the efficacy of chemoradiotherapy in patients with LD-SCLC.
Methods: We retrospectively analyzed 124 patients who underwent chemoradiotherapy for LD-SCLC at two institutions between April 2007 and June 2021, and assessed the prognostic significance of various metabolic and inflammatory markers. The GPS was calculated using the CRP and albumin concentrations, and categorized as follows: 0, CRP<1.0 mg/dL and albumin≥3.5 mg/dL; 1, elevated CRP or decreased albumin; and 2, CRP≥1.0 mg/dL and albumin<3.5 mg/dL. Differences in progression-free survival (PFS) and overall survival (OS) were examined using Kaplan–Meier curves and Cox proportional-hazard models.
Results: The overall response rate was 95.1% (95% confidence interval [CI]: 89.6–97.9%). The median PFS and OS from chemoradiotherapy initiation were 12.6 (95% CI: 9.9–15.4) and 29.0 (95% CI: 24.8–45.5) months, respectively. The GPS demonstrated independent predictive ability for the effectiveness of chemoradiotherapy, wherein favorable scores (GPS 0–1) were significantly correlated with superior PFS and OS compared to unfavorable scores (GPS 2: PFS: 14.8 vs. 6.7 months, p=0.0001; OS: 35.4 vs. 11.0 months, p<0.0001).
Conclusion: This preliminary examination revealed that the GPS was significantly associated with PFS and OS in patients undergoing chemoradiotherapy for LD-SCLC, indicating its potential utility in assessing the therapeutic outcomes in LD-SCLC.