PB2013 LACTATE DEHYDROGENASE LEVEL IS ASSOCIATED WITH A WORSE OUTCOME IN TURKISH PATIENTS WITH HAIRY CELL LEUKEMIA

Background: Hairy cell leukemia (HCL) is a rare B‐cell lymphoproliferative disorder. It manifests with cytopenia, hepatosplenomegaly, recurrent infections and constitutional symptoms due to the accumulation of malignant cells in hematopoetic tissues. Despite the indolent nature of HCL, it progresses with relapse and remission periodsHairy cell leukemia (HCL) is a rare B‐cell lymphoproliferative disorder. It manifests with cytopenia, hepatosplenomegaly, recurrent infections and constitutional symptoms due to the accumulation of malignant cells in hematopoetic tissues. Despite the indolent nature of HCL, it progresses with relapse and remission periods Aims: The aim of this study was to investigate risk factors at diagnosis which play a role in the occurrence of relapse after purine analogue treatment. Methods: This multicentre retrospective study of 65 HCL patients from 4 different centres was conducted between January 2000 and May 2018. Analysis was made of the demographic characteristics, initial hematological and biochemical parameters, splenectomy history, presence of organomegaly and LAP, bone marrow (BM) fibrosis, and the clinical and biological presentation at the time of HCL diagnosis.BM biopsy was performed at 3‐6 months after cladribine treatment for response evaluation. Results: The total 65 HCL patients comprised 47 (72.2%) males and 18 (27.3%) females with a median age of 53.6 years (range, 34‐80 years). The median follow‐up duration was 62.8 months (range: 5.7–229.3 months). Splenectomy was determined in the medical history of 2 patients with an unknown etiology.Cladribine monotherapy was administered as first‐line treatment in 60 patients (92.3%), and 5 patients (7.7%) who did not meet the treatment criteria were followed up without treatment. Of the treated patients, CR was achieved in 54 patients (90%), and PR was achieved in 3 patients (5%) with the overall response rate (CR+PR) of 95%. SD was determined in the remaining 3 patients (5%) after first‐line therapy. A total of 16 (24.4 %) patients either relapsed or progressed, with a median progression‐free survival of 47 months (25‐112 months). The analysis results showed that patients with relapse or progressive disease had higher LDH levels at the time of diagnosis than patients without relapse or progression (p:0.01).With the exception of lactate dehydrogenase (LDH) level at diagnosis, no significant difference was determined between these groups in respect of spleen and liver size, peripheral LAP, BM fibrosis score, hematological parameters, vitamin B12, ferritin levels, sedimentation and flow cytometric results Summary/Conclusion: This study demonstrated that an initial elevated LDH level is associated with a worse outcome in HCL patients. Patients with higher LDH levels may experience relapse or progression more frequently, therefore, the LDH level should be taken into account when deciding on treatment and those patients should be monitored more carefully. Aggressive treatment approaches such as combination therapies with monoclonal antibodies and PA may be considered as induction treatment. LDH level can be recommended for use as an inexpensive and easily available biomarker for risk assessment of HCL patients at onset.