Outcomes of HTLV-1 Carriers with Diffuse Large B-Cell Lymphoma: A Single-Center Retrospective Matched Cohort Study

Background: The human T-cell lymphotropic virus type 1 (HTLV-1) is associated with aggressive diseases, such as adult T-cell leukemia/lymphoma (ATLL). However, less is known on the impact of HTLV-1 infection in non-ATLL hematologic malignancies. We aimed to investigate if HTLV-1 carriers with diffuse large B-cell lymphoma (DLBCL) have worse survival outcomes than non-HTLV-1 carriers. Materials and Methods: We performed a single-center retrospective cohort study by matching HTLV-1 carriers to non-carriers based on age, sex, Ann Arbor stage, and year of diagnosis. Our outcomes of interest were overall survival (OS) and progression-free survival (PFS). The Kaplan-Meier method was used to estimate OS and PFS between carriers and non-carriers. We fitted multivariate Cox regression models to assess the mortality and recurrence/disease progression risk of HTLV-1 infection. Results: A total of 188 patients, 66 with HTLV-1 infection and 122 without HTLV-1, were included in the study. HTLV-1 carriers had higher extranodal involvement than non-carriers (47% vs. 27%, P = .010). With a median follow-up of 78 months (95% CI: 41-90 months), HTLV-1 carriers had a similar 5 year OS (41% vs. 42%, P = .940) and PFS (34% vs. 32%, P = .691) compared to non-carriers. In the multivariate Cox analysis, HTLV-1 infection was not associated with worse OS (aHR: 0.98, 95% CI: 0.64-1.50) or PFS (aHR: 0.90, 95% CI: 0.60-1.34). Conclusion: HTLV-1 carriers with DLBCL did not have worse survival outcomes compared to non-carriers. Our results suggest that clinicians should follow standard guidelines for DLBCL management on HTLV-1 seropositive patients.