S1645 NEUTROPHIL TO LYMPHOCYTE RATIO, PLATELET TO LYMPHOCYTE RATIO, AND RISK OF THROMBOEMBOLISM IN PATIENTS WITH LYMPHOMA RECEIVING CHEMOTHERAPY

Abstract

Background: Thromboembolism (TE) is one of major causes of morbidity and mortality in patients with malignancy. Pathophysiological connection between TE and inflammation has been established and it is being thoroughly studied recently. The neutrophil to lymphocyte ratio (NLR) and the platelet to lymphocyte ratio (PLR) are biomarkers for systemic inflammation. Principal advantage of NLR and PLR is their modest computability from complete blood count (CBC). NLR and PLR have been proven to have predictive ability of deep vein thrombosis presence, and demonstrated better predictive performances to D-dimer test. NLR and PLR have been reported to predict prognosis of acute pulmonary embolism (PE). Several publications showed predictive strength of high NRL for development of venous thromboembolism (VTE) in cancer patients receiving chemotherapy. However, the prognostic values of the NLR and PLR in patients with lymphoma have not been elucidated. Aims: We aimed to investigate the association between NLR, PLR and future risk of TE, in a prospective cohort of lymphoma patients receiving chemotherapy. Methods: A total of 484 patients who were diagnosed with lymphoma (including non-Hodgkin and Hodgkin lymphoma; excluding chronic lymphocytic leukemia/small lymphocytic lymphoma) at the Clinic for Hematology, Clinical Centre of Serbia, were prospectively included in the study. Data for newly diagnosed and relapsed patients who had completed a minimum of one chemotherapy cycle, were collected for all venous and arterial TE events from time of diagnosis to 3 months after the last cycle of therapy. NLR and PLR were calculated according to the CBC with differential count. TE was diagnosed based on radiographic studies (duplex venous ultrasound, contrast-enhanced thoracic computed tomography scan, magnetic resonance imaging (MRI) - for central nervous system (CNS) thrombosis, or angiograms (for arterial thrombosis), clinical examination, and laboratory evaluation. All probable cases of TE were reviewed by a final diagnosis committee composed of two specialists (internist and radiologist). Logistic regression analysis and ROC curve were performed to assess the association of NLR and PLR with TE. Results: The mean patients’ age was 53 years (range, 18–89 years); 52.3% were males. Most patients were newly diagnosed and had advanced stage disease: Ann Arbor stage III 21.1% and stage IV, 42.5%. A total of 242 patients (50.0%) had high-grade NHL; 137 (28.3%) had low-grade NHL; 84 (17.4%) had HL; 21 (4.3%) had other forms. 35 (7.2%) patients developed thromboembolic events. There were 30 patients with venous TE (6.2%), and 6 with arterial TE (1.2%), while one patient had both. NLR and PLR were significantly higher in TE patients compared to patients without TE (p = 0.001 and p = 0.002, respectively). The NLR was positively associated with PLR (p < 0.001). A positive NLR was considered 3.1 or higher, while a positive PLR was a ratio of 10 or more. The ROC curve analysis demonstrated acceptable specificity and sensitivity of NLR and PLR in predicting TE. NLR and PLR were found to be prognostic factors for the TE in lymphoma patients (relative risk [RR] = 4.1, 95% confidence interval [CI] = 1.9–8.7, p < 0.001 and RR = 2.9, 95% CI = 1.3–6.3, p = 0.008, respectively). In multivariate model NLR was found to be independent prognostic factors for the TE (RR = 4.5, 95% CI = 2.1–9.9, p < 0.001). Summary/Conclusion: The NLR and PLR demonstrated significant powerfulness in prediction of future risk of TE in lymphoma patients. Simplicity, effectiveness, modesty and practicability qualify these new tools for routine TE prognostic assessment.