Outcomes of patients with adult T-cell leukemia/lymphoma at a university and a public cancer center in Brazil.

OBJECTIVE: This study aimed to characterize adult T-cell leukemia/lymphoma (ATLL) cases in Brazil, a human T-cell lymphotropic virus type 1 (HTLV-1) endemic country, focusing on clinical presentation, diagnostic patterns, and prognostic factors, in order to address potential underdiagnosis and improve disease recognition and management. METHODS: A retrospective observational study was conducted at the University of São Paulo reviewing medical records of patients diagnosed with ATLL between 1994 and 2022. RESULTS: Fifty-five patients were included in this study: 29 (52.7%) had indolent ATLL (smoldering/chronic), seven (12.7%) had the lymphoma subtype, and 19 (34.5%) had the acute form. Among the indolent cases, 19 were previously identified as asymptomatic HTLV-1 carriers. HTLV-1 infection was only discovered at ATLL diagnosis in 56% of patients, including 77% among those with aggressive forms. Among known carriers, the median time from HTLV-1 diagnosis to ATLL onset was 9.9 years. Fourteen patients with indolent disease progressed to aggressive ATLL, with a median time of two years and median survival of 55 days after progression. Median overall survival varied by subtype: 68 months (smoldering), 41 (chronic), 13 (lymphoma), and 12.5 (acute). Among 36 patients treated with chemotherapy for aggressive disease, only 22% responded. Cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisone was the most common regimen. Only four patients underwent allogeneic stem cell transplantation; one remains alive at seven years. CONCLUSION: Adult T-cell leukemia/lymphoma remains underdiagnosed and poorly characterized in Brazil. Many patients present with or progress to aggressive disease with poor outcomes. These findings underscore the need for improved human T-cell lymphotropic virus type 1 screening, earlier diagnosis, and preventive strategies to reduce disease burden.