Risk factors of venous thromboembolic events among diffuse large B-cell lymphoma patients receiving first-line treatment

Abstract

BackgroundVenous thromboembolic events (VTEs) remain a major cause of mortality and morbidity among lymphoma patients. Accurate risk-prediction models are lacking, however, especially in the high VTE risk subgroup of diffuse large B-cell lymphoma (DLBCL). The relationship between patient-, disease- and treatment-related factors and the VTE risk is yet incompletely defined in this disease entity. MethodsIn this retrospective study, we analyzed the risk factors for VTEs in DLBCL patients treated with first-line (1L) chemoimmunotherapy in Kuopio and Oulu University Hospitals (2010-2019). Univariate and multivariate analysis (Cox regression) of VTE risk factors was performed. Two novel VTE risk scores were developed and compared by ROC (receiver operating characteristic) analysis.ResultsVTE occurred in 17.2% (n=59) in the whole population, of which seven cases occurred during anticoagulant therapy. Statistically significant risk factors for VTE included age >65 years, ECOG (Eastern Cooperative Oncology Group) >1, thrombophilia, bulky disease, LDH > ULN (lactate dehydrogenase; upper limit of normal) and IPI (International Prognostic Index) 4-5. In a multivariate Cox regression model, previous history of thrombophilia and bulky disease were independent risk factors for VTE (p=0.000 and p=0.032, respectively). VTE at 1L had no significant effect on survival (overall survival, progression-free survival or disease-specific survival) at 2 or 5 years of follow-up. Two different VTE risk scores were tested in DLBCL patients treated in 1L. ROC analysis was used to assess the ability of the score to classify VTE risk. A risk score 2 (age >65/LDH > ULN/ ECOG>1/thrombophilia = 1 p., bulky disease 2 p.) received a higher ROC value (0.680) than risk score 1. In the “high risk” group (5 p., according to risk score 2), VTE risk was increased, at 35.3%. ConclusionsThrombophilia and bulky disease were independent risk factors for VTE in 1L-treated DLBCL patients. A novel VTE risk score was developed, to be further qualified.