Retrospective Evaluation of Hairy Cell Leukemia Patients: Analysis of a Long-Term Single Center Data.

Background: Hairy cell leukemia (HCL) is a distinct lymphoproliferative disorder with unique circulating lymphocyte morphology. It is now regarded as an indolent disease yet treatable with purine analogs. We are going to present a complete long-term clinical and prognostic report of our HCL patients as a large cohort in Iran. Materials and Methods: All patients diagnosed with HCL, according to the World Health Organization (WHO) criteria, were enrolled in this study. They were referred to our academic center between 1995 and 2020. Treatment with a daily cladribine regimen was initiated as indicated and patients were followed. Survival data and clinical outcomes of patients were calculated. Results: A total of 50 patients were studied (76% male). The median time to treatment was 4.8 months and complete remission was achieved in 92% of patients. Nine patients (18%) experienced relapse with a median time to relapse of 47 months. After a median follow-up of 51 months, the median OS was not reached and after 234 months, the overall survival rate was 86%. Survival was worse in patients with non-classic HCL (vHCL) compared to classic HCL. Conclusion: Our long-term follow-up data confirmed the favorable outcomes of Iranian HCL patients with cladribine and provide a useful viewpoint of the disease.