To assess the distribution of Peripheral T-cell lymphomas (PTCL) across Latin America (LATAM) countries and report treatment outcomes.

Patients aged ≥18 years with newly diagnosed PTCL from the retrospective registry of the Grupo de Estudio Latinoamericano de Linfoproliferativos (GELL, n = 988, 1975-2023), T-cell Brazil Project (Brazilian TCP, ambispective registry 2015-2023, 593 cases) and the prospective International T cell Project (ITCP, n = 529, 2006-2023). Survival data was available from the GELL and Brazilian TCP. Overall survival (OS) was from diagnosis to death from any cause, while progression-free survival (PFS) was diagnosis to relapse, progression, or death from any cause and it was applied Kaplan-Meier method and Log-rank test.

Previous studies evaluating the distribution of PTCL subtypes across (LATAM) were limited in their representation of most countries in the region, however, now it was conducted an international pooled analysis and 11 countries of LATAM had enrolled. Besides that, a lack of standardized management for several subtypes and the absence of comprehensive lymphoma registries in LATAM suggests exploring real-world treatment patterns and clinical outcomes.

a total of 2110 pts from 11 LATAM countries were enrolled. Overall, the median age at dx was 54 years (18-95), 59% male, 67% had advanced stage disease and 29% had ECOG >1. The most frequently diagnosed PTCL subtypes was 39% PTCL not otherwise specified (NOS), 18% adult T-cell leukemia/lymphoma (ATL) and 16% extranodal NK/T cell lymphoma (ENKTL). Peru had a higher prevalence of ATL (39%) and ENKTL (43%) was frequently diagnosed in Central America. In contrast, ALK-negative (ALK-) anaplastic large T-cell lymphoma (ALCL) was the second in Brazil (18%), Chile (16%) and Argentina (9%); T-cell NOS was 28% in Chile and 27% in Argentina. First-line chemotherapy (CT) varied across subtypes and 77% received CT. Pts with ENKTL were frequently treated with asparaginase/platinum-based therapy (62%), while CHOP was used for ATL or PTCL NOS (46% for both). CT with CHOEP/EPOCH was used with ALK- ALCL (45%), ALK+ (47%), or AITL (48%). A median follow-up of 33 months, the 3-year OS and PFS were 40% and 30%, respectively. ALK+ ALCL had superior survival, with 77% OS and 73% of PFS. The ENKTL was 48% of OS and 45% PFS. Pts with ATL had the lowest survival rates (23% OS and 16% PFS). The use of asparaginase/platinum or CHOP-based therapy was associated with superior 3-year OS (61% and 52%, respectively; p = 0.011) and PFS (57% and 49%, respectively; p = 0.017) among pts with ENKTL. For ATL, the use of CHOEP/EPOCH was associated with improved 3-year OS (21%, p = 0.009) and PFS (15%, p = 0.024).

To our knowledge, this is the largest pooled cohort of PTCL subtypes across LATAM. Our findings suggest a distinct distribution of PTCL subtypes, with a higher prevalence of ATL and ENKTL compared to the epidemiological patterns in Western countries. The relatively high percentage of PTCL-NOS suggests difficulties in providing specific lymphoma diagnoses in the region. The low survival rates for some subtypes indicate the need to develop novel therapies to improve patient outcomes. A larger prospective assessment of PTCL epidemiology and treatment outcomes is being planned to expand the ascertainment of cases, improve pathological classification of the different PTCL subtypes, and validate our results in the LATAM region.