Real-World Outcomes and Prognostic Factors in Adult T-Cell Leukemia/Lymphoma: A 10-Year Romanian Cohort

Background/Objectives: Adult T-cell leukemia/lymphoma (ATL) is a rare and aggressive mature T-cell neoplasm associated with human T-cell lymphotropic virus type 1 (HTLV-1). Epidemiologic and clinical data from Eastern Europe remain limited despite the documented presence of HTLV-1 infection in the region. We aimed to characterize the clinical presentation, treatment patterns, survival outcomes, and prognostic factors of patients with ATL treated at a tertiary hematology referral center in Romania. Methods: We conducted a retrospective, single center cohort study of patients diagnosed with ATL at the Fundeni Clinical Institute, Bucharest, Romania, between 2014 and 2024. ATL diagnosis integrated compatible clinical, morphologic, immunophenotypic, and/or histopathologic findings with documented HTLV-1 infection; HTLV-1 was initially assessed by ELISA, with additional confirmatory testing used when available. Clinical, laboratory, treatment, response, and survival data were analyzed. Baseline demographic and biologic variables were compared between acute and lymphoma type ATL. Progression-free survival (PFS) and overall survival (OS) were evaluated using Kaplan–Meier methods and Cox proportional hazards regression. Results: Forty-five patients with ATL were identified: 23 with acute type (51.1%), 15 with lymphoma type (33.3%), 4 with smoldering type (8.9%), and 3 with chronic type disease (6.6%). Median age at diagnosis was 45.5 years, and the sex distribution was approximately balanced. Baseline leukocyte counts were higher in acute type than in lymphoma type ATL. Among patients with aggressive ATL, median baseline lactate dehydrogenase (LDH) was 827 U/L. CHOP or CHOP-like regimens were the predominant first line treatment strategy (80.6%), and zidovudine based therapy, with or without interferon, was administered to 52.6% of patients with aggressive ATL. Complete or partial response to first line therapy was associated with significantly better outcomes. Among patients with aggressive ATL, median PFS was 5.03 months and median OS was 9.17 months. Younger age (≤45 years) was associated with longer PFS and OS in univariable analyses. In univariable Cox analysis, higher baseline LDH was associated with inferior PFS (HR 1.060 per 100 U/L increase, 95% CI 1.017–1.104; p = 0.006). Response to first line therapy was evaluated separately as a post-treatment association. Zidovudine based therapy was associated with improved PFS and OS in univariable Kaplan–Meier analyses. Conclusions: This Romanian real world cohort confirms the aggressive clinical course and poor survival of ATL, particularly its acute and lymphoma subtypes. Higher baseline LDH was associated with inferior PFS, while achievement of CR or PR after first line therapy was associated with substantially longer PFS and OS. Patients who underwent allo-HSCT experienced favorable survival in exploratory Kaplan–Meier analyses; however, this observation should be interpreted cautiously because of the small number of transplanted patients and the potential for selection and immortal time bias. These findings underscore the need for earlier diagnosis, improved HTLV-1 screening, and access to contemporary therapeutic approaches in European settings outside the major traditionally recognized HTLV-1 endemic regions.