Ferritin and LDH predict thrombotic risk beyond conventional scoring systems in DLBCL

Thrombotic events are clinically significant complications in diffuse large B-cell lymphoma (DLBCL) that adversely affect treatment continuity and outcomes. Despite their importance, no standardized predictive approach exists, and traditional cancer-associated thrombosis models perform suboptimally in hematological malignancies. We retrospectively analyzed 133 adult patients with DLBCL treated at a single center between 2009 and 2021. Thrombotic events required objective radiological confirmation. Baseline demographic, clinical, and laboratory parameters were compared between patients with and without thrombosis. ROC analysis determined the optimal ferritin cutoff, and Cox proportional hazards and Fine-Gray competing-risk models (with death as a competing event) identified independent predictors. Thrombosis occurred in 16 patients (12.0%), all venous. Baseline clinical characteristics and the Khorana score did not differ between groups. Patients with thrombosis had significantly higher ferritin (median 331.5 vs. 113 ng/mL; p = 0.026) and LDH (median 459.5 vs. 256 U/L; p = 0.022). ROC analysis identified a ferritin cutoff of ≥ 227 ng/mL (AUC 0.686, 95% CI 0.532-0.840), associated with a 6.1-fold increased risk (OR 6.10, 95% CI 1.75-21.28). In multivariate Cox regression, ferritin ≥ 227 ng/mL (HR 3.77, 95% CI 1.13-12.60, p = 0.031) was an independent predictor and remained significant in competing-risk analysis (sHR 4.68); LDH was significant in Cox analysis (HR 1.002 per unit increase, p = 0.034) but was attenuated in the competing-risk model. In DLBCL, where no standardized thrombosis risk-stratification approach exists, elevated ferritin at diagnosis independently predicted thrombotic events, while LDH was significant in univariate analysis. These readily available parameters may contribute to lymphoma-specific thrombosis scoring systems and warrant prospective validation.