Early histological transformation of follicular lymphoma to diffuse large B-cell lymphoma indicating adverse survival: A population-based analysis and validation.

INTRODUCTION: The histological transformation (HT) of follicular lymphoma (FL) is a crucial biological event. The study aimed to evaluate the incidence, clinicial characteristics, prognosis and impact of HT time on survival of FL transforming to diffuse large B-cell lymphoma in population-based large-scale cohorts. METHODS: A retrospective cohort study of FL with HT was performed in the Surveillance, Epidemiology, and End Results database. The Hematological Malignancy Research Network FL cohort and Aristotle study FL cohort were used to assess the external validity. RESULTS: Among 44,127 FL cases from the Surveillance, Epidemiology, and End Results database, 1311 cases were pathology-proven recorded to transform to diffuse large B-cell lymphoma. The cumulative rates of HT at 5, 10, and 15 years after FL diagnosis were estimated to be 1.19%, 2.93%, and 5.01%, respectively. Significantly worse overall survival and cancer-specific survival were exhibited in patients with HT than those without HT. Early HT (transformation of FL within 48 months after FL diagnosis [TOD48]) was an independent predictor for adverse overall survival of HT patients, regardless of treatment modalities before transformation. The adverse prognostic effect of TOD48 was validated in the Hematological Malignancy Research Network cohort and Aristotle study cohort. Older age (>75 years) and B symptoms within FL at diagnosis were the independent risk factors of TOD48. Furthermore, a novel prognostic model combining TOD48 with Follicular Lymphoma International Prognostic Index (TOD48-FLIPI) was constructed and validated for risk stratification. CONCLUSION: TOD48 was a risk indicator of HT, and the novel prognostic model "TOD48-FLIPI" for HT patients was proposed.

Outcome of malignant lymphoma in Ukraine. Analysis of 563 cases registered in the Ukrainian Lymphoma Registry in 2019-2021.

We report the outcome of 563 cases of newly diagnosed lymphoma registered in 2019-2021, including 176 cases (31.2%) of Hodgkin lymphoma (HL), 130 (23.1%) of diffuse large B-cell lymphoma (DLBCL), 28 (5%) of follicular lymphoma (FL), 16 (2.9%) of mantle cell lymphoma (MCL) and 20 (3.5%) of peripheral T-cell lymphoma (PTCL). After a median follow-up of 30.1 months (95% CI: 28.8-31.3), the 3-year overall survival rates were 95%, 83%, 86%, 100%, 61% and 42% for HL, DLBCL, CLL, FL, MCL and PTCL respectively. These data offer valuable information on the curability of lymphoma patients in Ukraine, in a real-world setting.

Long-term outcome of peripheral T-cell lymphomas: Ten-year follow-up of the International Prospective T-cell Project.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of haematological cancers with generally poor clinical outcomes. However, a subset of patients experience durable disease control, and little is known regarding long-term outcomes. The International T-cell Lymphoma Project (ITCLP) is the largest prospectively collected cohort of patients with PTCLs, providing insight into clinical outcomes at academic medical centres globally. We performed a long-term outcome analysis on patients from the ITCLP with available 10-year follow-up data (n = 735). The overall response rate to first-line therapy was 68%, while 5- and 10-year overall survival estimates were 49% and 40% respectively. Most deaths occurred prior to 5 years, and for patients alive at 5 years, the chance of surviving to 10 years was 84%. However, lymphoma remained the leading cause of death in the 5- to 10-year period (67%). Low-risk International Prognostic Index and Prognostic Index for T-cell lymphoma scores both identified patients with improved survival, while in multivariate analysis, age >60 years and Eastern Cooperative Oncology Group performance status 2-4 were associated with inferior outcomes. The favourable survival seen in patients achieving durable initial disease control emphasizes the unmet need for optimal front-line therapeutic approaches in PTCLs.

A 12-Month Analysis of the Dermatologic Effects and Durability of Midface Volume Correction With DEFCL Volumizing Filler in a Prospective, Single-Center Study.

BACKGROUND: Certain manufacturing processes confer distinctive rheologic features to hyaluronic acid (HA), ensuring long-lasting effects. Skin quality improvement and the volumizing effects of the DEFCL volumizer filler, a sterile, biodegradable, viscoelastic, transparent, isotonic, and homogenized injectable cross-linked high G' filler for the treatment of moderate-to-severe age-related midface changes, were initially documented at 6 months after the first injection. OBJECTIVE: The authors aimed to objectively evaluate the effects of the DEFCL volumizer filler in improving skin density, thickness, and biomechanical properties and on tissue volume augmentation in women with midface volume loss after 12 months. MATERIALS AND METHODS: Fifty women with midface volume loss were recruited in this prospective, noncomparative, single-center, postmarket study. The authors report changes in skin density, thickness, and quality and subjective and objective evaluation of facial and/or cheek volume augmentation using the Global Aesthetic Improvement Scale, as well as injection site reactions and adverse events. RESULTS: Improvements in skin quality and thickness and volumization were maintained 12 months after the first injection. Injector and patient satisfaction were highly rated with only mild adverse reactions observed. CONCLUSION: Skin improvement and volumizing effects persisted in patients treated with the DEFCL volumizer after 12 months.

Outcomes and prognostic factors in angioimmunoblastic T-cell lymphoma: final report from the international T-cell Project.

Angioimmunoblastic T-cell lymphoma (AITL) is a unique subtype of peripheral T-cell lymphoma (PTCL) with distinct clinicopathologic features and poor prognosis. We performed a subset analysis of 282 patients with AITL enrolled between 2006 and 2018 in the international prospective T-cell Project (NCT01142674). The primary and secondary end points were 5-year overall survival (OS) and progression-free survival (PFS), respectively. We analyzed the prognostic impact of clinical covariates and progression of disease within 24 months (POD24) and developed a novel prognostic score. The median age was 64 years, and 90% of patients had advanced-stage disease. Eighty-one percent received anthracycline-based regimens, and 13% underwent consolidative autologous stem cell transplant (ASCT) in first complete remission (CR1). Five-year OS and PFS estimates were 44% and 32%, respectively, with improved outcomes for patients who underwent ASCT in CR1. In multivariate analysis, age ≥60 years, Eastern Cooperative Oncology Group performance status >2, elevated C-reactive protein, and elevated ß2 microglobulin were associated with inferior outcomes. A novel prognostic score (AITL score) combining these factors defined low-, intermediate-, and high-risk subgroups with 5-year OS estimates of 63%, 54%, and 21%, respectively, with greater discriminant power than established prognostic indices. Finally, POD24 was a powerful prognostic factor with 5-year OS of 63% for patients without POD24 compared with only 6% for patients with POD24 (P < .0001). These data will require validation in a prospective cohort of homogeneously treated patients. Optimal treatment of AITL continues to be an unmet need, and novel therapeutic approaches are required.

Distribution of lymphoma subtypes in Ukraine according to the WHO 2016 classification.

The Ukrainian Lymphoma Registry (ULR) was established in 2019 with the aim of monitoring the quality of diagnosis, staging, and treatment of lymphoma in Ukraine. Between September 2019 and October 2021, 546 patients with newly diagnosed lymphoma were prospectively registered. All cases were diagnosed according to the 2016 updated WHO lymphoma classification. The male-to-female ratio (M/F) for the whole population was 0.7, with a median age of 46 years (range 18-95). The adoption of the 2016 WHO classification resulted in the identification of 36 different lymphoma subtypes, with 132 cases (24.2%) classified differently compared to the 2008 WHO classification. Only 12 cases (2.8%) were true new entities, including seven cases of high-grade B-cell lymphoma NOS, three of anaplastic large B-cell lymphoma, ALK-negative, 1 case of HHV8+ DLBCL NOS, and 1 of high-grade B-cell lymphoma with C-MYC and BCL2/BCL6 rearrangement. Moreover, 55 (61.1%) entities, including 37 defined by WHO 2008 and 18 defined by WHO 2016, were not represented at all. The analysis of cases registered in the ULR provides a comprehensive breakdown of the subtypes, stage distribution, and treatment of malignant lymphomas (ML) in Ukraine, supporting the usefulness of prospective data collection and timely reporting. We believe that this study is the first step toward a better understanding of the real-life outcomes of patients with ML.

Impact of immunochemotherapy with R-bendamustine or R-CHOP for treatment naïve advanced-stage follicular lymphoma: A subset analysis of the FOLL12 trial by Fondazione Italiana Linfomi.

We conducted a post hoc analysis of the FOLL12 trial to determine the impact of different initial immunochemotherapy (ICT) regimens on patient outcomes. Patients were selected from the FOLL12 trial, which included adults with stage II-IV follicular lymphoma (FL) grade 1-3a and high tumor burden. Patients were randomized 1:1 to receive either standard ICT followed by rituximab maintenance (RM) or the same ICT followed by a response-adapted approach. ICT consisted of rituximab-bendamustine (RB) or rituximab, cyclophosphamide, doxorubicin, and prednisone (R-CHOP), per physician's decision. A total of 786 patients were included in this analysis, 341 of whom received RB and 445 R-CHOP. RB was more frequently prescribed to older subjects, females, patients without bulky disease, and those with grade 1-2 FL. After a median of 56 months of follow-up, R-CHOP and RB had similar progression-free survival (PFS) (Hazard Ratio for RB 1.11, 95% CI 0.87-1.42, p = 0.392). Standard RM was associated with improved PFS compared to response-adapted management both after R-CHOP and RB. Grade 3-4 hematologic adverse events were more frequent with R-CHOP during induction treatment and more frequent with RB during RM. Grade 3-4 infections were more frequent with RB. RB was also associated with a higher incidence of transformed FL. R-CHOP and RB showed similar activity and efficacy, but with different safety profiles and long-term events, suggesting that the treating physician should carefully select the most appropriate chemotherapy regimen for each patient based on patient's individual characteristics, choices, and risk profile.

An Interim 6-Month Analysis of the Dermatologic Effects and Midface Volume Correction With XTR CL Filler in a Prospective, Single-Center Study.

BACKGROUND: Hyaluronic acid-based filler injections with parenteral anesthetics have become the standard in treating midface volume deficits. There are currently limited data on the effects of these types of fillers on skin density, thickness, and firmness. OBJECTIVE: This study aimed to assess the efficacy of XTR CL filler in improving skin quality and tissue volume in women with midface volume loss. MATERIALS AND METHODS: In this prospective, noncomparative, single-center study, 50 women aged between 40 and 60 years with midface volume loss were recruited. The primary endpoint was the improvement in investigator-assessed Global Aesthetic Improvement Scores (GAIS) 1 month after treatment. Secondary endpoints include objective measurements of skin density, thickness, and quality measurements, facial and/or cheek volume augmentation, subjective GAIS, and device evaluation from after the first injection until 6 months, and the documentation of injection site reactions and adverse events. RESULTS: XTR CL use led to significant improvement in midface volume deficits, and skin quality and skin thickness. Injector and subject satisfaction with the treatment were documented and only mild-to-moderate adverse reactions were reported. CONCLUSION: XTR CL was shown to be effective in improving volume loss and skin quality at 6 months.

Characteristics and clinical outcomes of patients with ALK-positive anaplastic large cell lymphoma: Report from the prospective international T-cell lymphoma project.

The T-cell Lymphoma Project is an international registry prospective study that enrolled patients with newly diagnosed peripheral T-cell and NK-cell lymphomas (PTCL). The main objective was to define the clinical features and outcomes, establishing a robust benchmark for future clinical trials. Seventy-four institutions from 14 countries in North America, South America, Europe, and Asia collected data on patients diagnosed and treated at their respective centers between September 2006 and February 2018. Among 1553 PTCL patients, 131 (8.4% of the total cohort) were confirmed to have anaplastic large cell lymphoma - kinase positive (ALCL, ALK+). The median age of the patients was 39 years (18-84). Sixty-five patients (66%) had advanced-stage disease, although majority (45 patients, 54%) had a low-risk International Prognostic Index (IPI) score (0-1). Of 97 patients treated with chemotherapy, 97% received anthracycline-containing regimens. The overall response rate was 81%, with 69 patients (70%) achieving complete remission. Estimated OS and PFS at 3 years were 77% (95% CI: 54%-99%) and 68% (95% CI: 46%-90%), respectively, and at 5 years were very similar, 77% of OS (95% CI: 62%-92%) and 64% of PFS (95% CI: 34%-94%). Multivariate analysis for PFS showed advanced stage (hazard ratios [HR]: 4.72, 95% CI: 1.43-23.9, p = 0.015), elevated lactate dehidrogenade (LDH) (HR 4.85; 95% CI: 1.73-13.60, p = 0.001), and Eastern Cooperative Oncology Group Performance Status scale (ECOG-PS) ≥2 (HR: 5.25; 95% CI: 1.68-16.4, p = 0.024). For OS, elevated LDH (HR: 3.77; 95% CI: 1.98-14.17, p = 0.014) and ECOG-PS ≥2 (HR: 4.59; 95% CI: 1.46-14.39, p = 0.004) were identified. In summary, although the outcome of ALK+ ALCL is superior to that of other PTCLs, it remains sufficiently favorable, given the young median age of the patients. Our results confirm the usefulness of both IPI and Prognostic Index for T-cell Lymphoma (PIT) in identifying groups of patients with different outcomes. Clinical Trials ID: NCT01142674.

Long-term results of the MCL01 phase II trial of rituximab plus HyperCVAD alternating with high-dose cytarabine and methotrexate for the initial treatment of patients with mantle cell lymphoma.

Mantle cell lymphoma is a rare and incurable lymphoproliferative disorder. In the MCL01 trial, patients were treated with the R-HCVAD regimen [rituximab plus HyperCVAD (hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone; R-CVAD) alternating with high-dose methotrexate and cytarabine (AM)] for four cycles followed by autologous stem cell transplantation (ASCT) for those who reached only a partial response. After a median follow-up of 10·5 years, we reported 10-year progression-free and overall survival rates of 35% and 61% respectively, with a 10-years cumulative incidence rate of second malignancies of 10·6%. Mature results of the MCL01 trial confirmed the efficacy of HyperCVAD-AM as a frontline regimen for younger patients (≤65 years).

Peripheral T cell lymphoma, not otherwise specified (PTCL-NOS). A new prognostic model developed by the International T cell Project Network.

Different models to investigate the prognosis of peripheral T cell lymphoma not otherwise specified (PTCL-NOS) have been developed by means of retrospective analyses. Here we report on a new model designed on data from the prospective T Cell Project. Twelve covariates collected by the T Cell Project were analysed and a new model (T cell score), based on four covariates (serum albumin, performance status, stage and absolute neutrophil count) that maintained their prognostic value in multiple Cox proportional hazards regression analysis was proposed. Among patients registered in the T Cell Project, 311 PTCL-NOS were retained for study. At a median follow-up of 46 months, the median overall survival (OS) and progression-free survival (PFS) was 20 and 10 months, respectively. Three groups were identified at low risk (LR, 48 patients, 15%, score 0), intermediate risk (IR, 189 patients, 61%, score 1-2), and high risk (HiR, 74 patients, 24%, score 3-4), having a 3-year OS of 76% [95% confidence interval 61-88], 43% [35-51], and 11% [4-21], respectively (P < 0·001). Comparing the performance of the T cell score on OS to that of each of the previously developed models, it emerged that the new score had the best discriminant power. The new T cell score, based on clinical variables, identifies a group with very unfavourable outcomes.

The outcome of peripheral T-cell lymphoma patients failing first-line therapy: a report from the prospective, International T-Cell Project.

This analysis explored factors influencing survival of patients with primary refractory and relapsed peripheral T-cell lymphomas enrolled in the prospective International T-cell Project. We analyzed data from 1020 patients with newly diagnosed disease, enrolled between September 2006 and December 2015. Out of 937 patients who received first-line treatment, 436 (47%) were identified as refractory and 197 (21%) as relapsed. Median time from the end of treatment to relapse was 8 months (range 2-73). Overall, 75 patients (8%) were consolidated with bone marrow transplantation, including 12 refractory and 22 relapsed patients. After a median follow up of 38 months (range 1-96 months) from documentation of refractory/relapsed disease, 440 patients had died. The median overall survival (OS) was 5.8 months; 3-year overall survival rates were 21% and 28% for refractory and relapsed patients, respectively (P<0.001). Patients receiving or not salvage bone marrow transplantation had a 3-year survival of 48% and 18%, respectively (P<0.001). In a univariate Cox regression analysis, refractory disease was associated with a higher risk of death (HR=1.43, P=0.001), whereas late relapse (>12 months, HR 0.57, P=0.001) and salvage therapy with transplantation (HR=0.36, P<0.001) were associated with a better OS. No difference was found in OS with respect to histology. This study accurately reflects outcomes for patients treated according to standards of care worldwide. Results confirm that peripheral T-cell lymphomas patients had dismal outcome after relapse or progression. Patients with chemotherapy sensitive disease who relapsed after more than 12 months might benefit from consolidation bone marrow transplantation.

Global outcomes and prognosis for relapsed/refractory mature T-cell and NK-cell lymphomas: Results from PETAL consortium.

Variances in global access to drugs and treatment practices make it challenging to understand the benefit of contemporary therapies in patients with relapsed and refractory (R/R) mature T-cell and NK-cell lymphomas (MTCL and MNKCL). We conducted an international retrospective cohort study of 925 patients with R/R MTCL and MNKCL. In PTCL-NOS and ALK- ALCL, patients with relapsed lymphoma demonstrated a superior median overall survival (OS) relative to refractory from the time of second-line treatment. We identified several independent predictors of OS for R/R lymphoma including age >60, primary refractory disease, histological subtype other than AITL, extranodal sites >1, Ki67 ≥40%, and absolute lymphocyte count

The SALENTO prognostic model for limited-stage peripheral T-cell lymphoma from the International T-Cell Project Network.

The natural history of limited-stage peripheral T-cell lymphomas (PTCLs) remains poorly defined. We investigated outcomes and prognostic variables in patients registered in the T-Cell Project (TCP) (#NCT01142674) to develop a model to predict overall survival (OS) for the common nodal PTCL subtypes (PTCL-NOS, AITL, ALCL). The model was validated in an independent data set from Australian and Brazilian registries. 211 patients registered in the TCP between 2006-2018 were studied. The median age was 59 years (range 18-88) and median follow-up was 49 months. One hundred twenty-seven patients (78%) received anthracycline-based regimens, 5 patients (3%) radiotherapy alone (RT), 24 patients (15%) chemotherapy+RT. 5-year OS and PFS were 47% and 37%, respectively. Age >60 years, elevated LDH and low serum albumin were independent prognostic factors. The model identified 3 groups with low- (26%, score 0), intermediate- (41%, score 1), and high-risk (33%, score 2-3) with 5-year OS of 78% (95% confidence interval [95% CI], 29-127), 46% (95% CI, 24-68), and 25% (95% CI, 20-30), respectively (P < 0.001) and 5-year PFS of 66% (95% CI, 33-99), 37% (95% CI, 9-65), and 17% (95% CI, 9-25), respectively (P < 0.001). The model demonstrated greater discriminatory power than established prognostic indices and an analogous distribution and outcomes in the 3 groups in the validation cohort of 103 patients. The SALENTO Model (Limited Stage Peripheral T-Cell Lymphoma Prognostic Model) is an objective, simple and robust prognostic tool. The high-risk group has poor outcomes, comparable to advanced stage disease, and should be considered for innovative first-line approaches.

Response-Adapted Postinduction Strategy in Patients With Advanced-Stage Follicular Lymphoma: The FOLL12 Study.

PURPOSE: We compared 2 years of rituximab maintenance (RM) with a response-adapted postinduction approach in patients with follicular lymphoma who responded to induction immunochemotherapy. METHODS: We randomly assigned treatment-naïve, advanced-stage, high-tumor burden follicular lymphoma patients to receive standard RM or a response-adapted postinduction approach on the basis of metabolic response and molecular assessment of minimal residual disease (MRD). The experimental arm used three types of postinduction therapies: for complete metabolic response (CMR) and MRD-negative patients, observation; for CMR and MRD-positive (end of induction or follow-up) patients, four doses of rituximab (one per week, maximum three courses) until MRD-negative; and for non-CMR patients, one dose of ibritumomab tiuxetan followed by standard RM. The study was designed as noninferiority trial with progression-free survival (PFS) as the primary end point. RESULTS: Overall, 807 patients were randomly assigned. After a median follow-up of 53 months (range, 1-92 months), patients in the standard arm had a significantly better PFS than those in the experimental arm (3-year PFS 86% v 72%; P < .001). The better PFS of the standard versus experimental arm was confirmed in all the study subgroups except non-CMR patients (n = 65; P = .274). The 3-year overall survival was 98% (95% CI, 96 to 99) and 97% (95% CI, 95 to 99) in the reference and experimental arms, respectively (P = .238). CONCLUSION: A metabolic and molecular response-adapted therapy as assessed in the FOLL12 study was associated with significantly inferior PFS compared with 2-year RM. The better efficacy of standard RM was confirmed in the subgroup analysis and particularly for patients achieving both CMR and MRD-negative.

Primary refractory follicular lymphoma: a poor outcome entity with high risk of transformation to aggressive B cell lymphoma.

BACKGROUND: Primary refractory (PREF) follicular lymphoma (FL) has a completely different clinical course from that of FL that responds to front-line treatments. In addition to having poor responses to salvage therapies, it seems that patients with PREF are at increased risk of histological transformation (HT). The Aristotle consortium presented the opportunity of investigating the risk of HT in a very large series of cases. Thus, we investigated the risk of HT in patients with PREF FL compared with that of responding patients or in stable disease and ultimately their outcome. METHODS: Six thousand three hundred thirty-nine patients from the Aristotle database were included in the analysis. These patients had a histologically confirmed grade 1, 2 or 3a FL diagnosed between 1997 and 2013. The primary end-points were the cumulative incidence (CI) of HT at the first progression or relapse and the survival after transformation. FINDINGS: The 5-year CI of HT among patients with PREF was 34% (95% confidence interval (CI): 27-43), whilst it was 7.1% (95% CI: 6.0-8.5) in the group of patients with partial response (PR) or stable disease (SD) (PR + SD) and 3.5% (95% CI: 3.0-4.2) in the group of patients achieving complete response (CR). The 5-year survival after relapse (SAR) was 33% (95% CI: 28-39) for the PREF group, 57% (95% CI 54-61) in patients with PR, 51% (95% CI 43-58) in the SD group after first-line therapy and 63% (95% CI: 66-72) in patients with CR after initial treatment (p-value <0.001). The 5-year SAR for those patients with PREF who developed HT was 21% (95% CI: 12-31), clearly diminished when compared with those patients with PREF who did not experience HT (38% [95% CI: 31-44]) (p-value = 0.001). INTERPRETATION: Patients with PREF FL have a dismal outcome and an associated very high rate of HT that further worsens their poor prognosis.

ALK-negative anaplastic large cell lymphoma: features and outcomes of 235 patients from the International T-Cell Project.

Anaplastic lymphoma kinase-negative anaplastic large cell lymphoma (ALK- ALCL) is an aggressive neoplasm of T-cell/null-cell lineage. The T-Cell Project is a global prospective cohort study that consecutively enrolled patients newly diagnosed with peripheral T-cell lymphoma, registered through a centralized computer database between September 2006 and February 2018. Of 1553 validated cases from 74 sites in 13 countries worldwide, 235 were reported as ALK- ALCL. The median age at diagnosis was 54 years (range, 18-89 years), with a male predominance (62%). Stage III to IV disease was identified in 71% of patients, bulky disease and bone marrow involvement were uncommon, and 66% of patients presented with a low (0-1) International Prognostic Index score. Of all treated patients, 85% received multiagent initial chemotherapy, and 8% were consolidated with autologous hematopoietic cell transplantation. The initial overall and complete response rates were 77% and 63%, respectively. After a median follow-up of 52 months (95% confidence interval [CI], 41-63), the median progression-free survival (PFS) and overall survival (OS) were 41 months (95% CI, 17-62) and 55 months (95% CI, 36-75), respectively. The 3- and 5-year PFS rates were 52% and 43%, and the 3- and 5-year OS rates were 60% and 49%. Treatments containing both anthracycline and etoposide were associated with superior OS (P = .05) but not PFS (P = .18). In this large prospective cohort study, outcomes comparable to those previously reported in the retrospective International Peripheral T-Cell Lymphoma Project were observed. The study underscores the need for introducing novel platforms for ALK- ALCL and establishes a benchmark for future clinical trials. This trial was registered at www.clinicaltrials.gov as #NCT01142674.

Survival outcomes of patients with extranodal natural-killer T-cell lymphoma: a prospective cohort study from the international T-cell Project.

BACKGROUND: Extranodal natural killer (NK) T-cell lymphoma (ENKTL) is a unique clinicopathological entity, typically associated with poor survival outcomes. Most published data have come from east Asian study groups, with little information available from international cohorts. The effects of treatment advances on routine clinical practice across continental territories has not been clear. We aimed to improve understanding of the clinical characteristics and outcomes of patients with ENKTL. METHODS: We did a substudy of patients with ENKTL from the T-cell Project, a global prospective cohort study. The T-cell Project registered consecutively diagnosed adults (>18 years) with newly diagnosed, untreated mature T-cell or NK lymphomas (WHO 2001 or 2008 classifications) from 74 centres in 13 countries (in Asia, Europe, North America, and South America). In total, 1695 patients with mature T-cell or NK lymphomas were enrolled between Oct 12, 2006 and Feb 28, 2018 in the T-cell Project. The first patient with ENKTL was enrolled on Feb 15, 2007, and the last on May 26, 2017. Data on baseline characteristics, first-line treatment, treatment response, and survival outcomes were recorded in a central database (locked March 30, 2019). The primary outcome was 5-year overall survival. The T-cell Project is registered on ClinicalTrials.gov, NCT01142674. FINDINGS: 166 patients were diagnosed with ENKTL, comprising 11% of 1553 eligible registered cases and distributed across 40 participating centres in four continents. At a median follow-up of 44 months (IQR 20-61), overall survival at 5 years was 54% (95% CI 44-63) in patients with nasal disease (n=98) and 34% (27-46) in patients with extranasal disease (n=68). INTERPRETATION: To our knowledge, this study presents the largest international cohort of patients with ENKTL. We describe a clinically significant improvement in the survival of patients with ENKTL treated in routine clinical practice over the past decade, likely to be attributable to the increasing use of treatment protocols specific for ENKTL. FUNDING: The Fondazione Cassa di Risparmio di Modena, the Associazione Angela Serra per la Ricerca sul Cancro, the Fondazione Italiana Linfomi, Allos Therapeutics, Spectrum Pharmaceuticals, Associazione Italiana per la Ricerca sul Cancro, and the National Cancer Institute at the National Institutes of Health.