Endothelial activation and stress index as a prognostic factor of diffuse large B-cell lymphoma: the report from the nationwide multi-center Thai Lymphoma Study Group.

Several prognostic models have been introduced to predict outcomes of patients with diffuse large B-cell lymphoma (DLBCL). Endothelial activation and stress index (EASIX) is a surrogate of endothelial dysfunction which has been shown to predict outcomes of patients with various hematologic malignancies. However, the prognostic implication of EASIX for DLBCL is limited and warrants exploration. We conducted a retrospective study enrolling adult DLBCL patients including a discovery cohort from the single-centered university hospital database and a validation cohort from the independent nationwide multi-center registry. EASIX scores were calculated using creatinine, lactate dehydrogenase, and platelet levels. The receiver operating characteristic curve analysis was used to determine optimal cutoff. Statistical analysis explored the impact of EASIX on survival outcomes. A total of 323 patients were included in the discovery cohort. The optimal EASIX cutoff was 1.07 stratifying patients into low (53.9%) and high EASIX (46.1%) groups. Patients with high EASIX had worse 2-year progression-free survival (PFS) (53.4% vs. 81.5%, p<0.001) and overall survival (OS) (64.4% vs. 88.7%, p<0.001) than patients with low EASIX. Multivariate analysis revealed that older age, bulky disease, impaired performance status, and high EASIX were associated with an unfavorable OS. In the validation cohort of 499 patients, the optimal EASIX cutoff was 1.04. Similar to the discovery cohort, high EASIX score was associated with high-risk diseases, worse PFS, and inferior OS. In conclusion, EASIX score was significantly associated with survival outcomes and may be used as a simple prognostic tool to better risk-classify DLBCL.