Endothelial activation and stress index (EASIX) as a predictive biomarker in small cell lung cancer

BACKGROUND: Endothelial activation and insult may contribute to the aggressive clinical course of small-cell lung cancer (SCLC); however, no predictive biomarker for this pathogenesis has been identified. OBJECTIVE: To evaluate the clinical impact of the endothelial activation and stress index (EASIX) in SCLC. METHODS: In this retrospective study, the EASIX was calculated from measurements of serum lactate dehydrogenase, creatinine, and platelet levels. A total of 264 patients with SCLC treated with platinum-based chemotherapy were stratified into high and low EASIX groups. RESULTS: Complete and objective response rates in the limited-stage (LD) were 19.5% vs. 33.3% (P= 0.050) and 85.4% vs. 97.9% (P= 0.028) in the high and low EASIX groups, respectively. There was no significant difference in the response rate between the two groups in the extensive-stage (ED). The median overall survival was 9.8 vs. 40.5 months in LD (P< 0.001) and 7.2 vs. 11.9 months in ED (P< 0.001) in the high and low EASIX groups, respectively. In multivariate analyses, a high EASIX level was an independent prognostic factor for worse progression-free and overall survival irrespective of stage. CONCLUSION: EASIX may be a potential predictive biomarker of SCLC.