T-cell Brazil project started in April 2017 focusing to collecting epidemiological and clinical data from the most frequent subtypes of PTCL, as an ambispective study collected diagnosis data from January 2015 to December 2022. Our goals were to obtain the frequency of subtypes and the clinical and biology characteristic from five Brazilian regions; besides to have a routine pathological revision and to evaluate the Overall Survival (OS), Progression-Free Survival (PFS) in 5 years of follow-up.

After 39 centers were approved by their Ethical Committee, they registered their cases using the REDcap Platform by Vanderbilt, being 63% public centers. Here, It was just analyzed a Prospective Cohort (PC), with diagnosis date from April 2017 to December 2022, a total of 461 cases. Descriptive analyses, Kaplan-Meier method, Log-Rank test to compare groups and Cox Regression to identify risk factor for OS using IBM-SPSS software v.24.

The median age was 52 years (18-92); 58% male; Almost 72% had advanced stages, 25% ECOG ≥ 2; the distribution of main subtypes was: 30% PTCL-NOS; 18% ALCL, ALK-; 14% ATL; 13% ENKTL-NT; 10.5% AITL; 5% ALCL, ALK+; 9.5% others. A median of follow up of 22 months (0-73), 55% pts were alive and 24-month PFS and OS were 36% and 49%, respectively. OS by main subtypes was 69% ALCL, ALK+; 61% ALCL, ALK; 50% PTCL-NOS; 44% ENKTL-NT; 41% AITL; 27% ATL. Cox regression showed ATL (HR 1.6, p = 0.008), ECOG ≥ 2 (HR 1.86, p < 0.0001) and Ann Arbor Stage III-IV (HR 2.06, p < 0.0001) as bad prognosis for OS; whereas for PFS were ATL (HR 1.9, p < 0.0001); ECOG≥ 2 (HR 1.53, p = 0.002); Ann Arbor Stage III-IV (HR 1.75, p = 0.001) and B symptoms (HR 1.36, p = 0.02). Discussion: PTCL make up approximately 10-15% of lymphoid malignancies and its frequency varies geographically. In Brazil, mainly due to its vast dimension, data collection has limitations and is subject to bias. This is the first experience cover all over the country, focusing also an educational and of interchanging experience network among the multidisciplinary health team in Brazil.

Our initial target of 500 pts exceeded, hence the number of prospective cohort is getting close, because we are in a consistency data phase and probably more cases will be available after that. So, it is possible to make analyzes with PC. ATL and ENKTL-NT subtype presented more frequent of all, different of the Occidental countries, but similar with recent data from American Latin.