Classification of non-Hodgkin lymphomas in Guatemala according to the World Health Organization system

Epidemiology, clinical features, and outcomes of peripheral T-cell lymphoma in Latin America: an international, retrospective, cohort study

BACKGROUND

Peripheral T-cell lymphomas represent a rare and heterogeneous group of mature T-cell neoplasms characterised by aggressive behavior. Previous studies evaluating peripheral T-cell lymphoma epidemiology across Latin America have been restricted in their representation of most countries in the region. In this study, we aimed to describe peripheral T-cell lymphoma epidemiology across Latin America.

METHODS

We did an international, retrospective, cohort study of patients (aged ≥18 years) with newly diagnosed peripheral T-cell lymphoma across 11 countries in Latin America (Argentina, Brazil, Chile, Colombia, Cuba, Guatemala, Mexico, Paraguay, Peru, Uruguay, and Venezuela). We used the hospital-based registries of the Grupo de Estudio Latinoamericano de Linfoproliferativos (retrospective registry; Jan 1, 2000, to June 30, 2023), the Brazilian T-cell Project (retrospective from Jan 1, 2015, to June 30, 2017 and prospective from July 1, 2017, to June 30, 2023), and the International T-cell Lymphoma Project (prospective registry). The main outcomes were prevalence of peripheral T-cell lymphoma subtypes, overall survival, estimated using the Kaplan-Meier method, and objective response rate. Survival probabilities were estimated using the Kaplan-Meier method and compared with the log-rank test. Overall response rate was calculated by summing complete and partial responses, with 95% CIs estimated using the Clopper-Pearson method.

FINDINGS

1979 patients diagnosed with peripheral T-cell lymphoma by pathology, between 2000 and 2023, met our inclusion criteria for the distribution analysis and 1349 were included in the treatment patterns and outcome analysis. Median age at diagnosis was 54 years (IQR 41-67), 733 (41%) of 1794 patients were female, and 1061 (59%) patients were male. The most common subtype was peripheral T-cell lymphoma, not otherwise specified (688 [35%] of 1979 patients); the second and third most frequent subtypes were adult T-cell leukaemia or lymphoma (333 [17%] of 1979 patients) and extranodal natural killer T-cell lymphoma (291 [15%] of 1979 patients). The next most common subtypes were ALK-negative anaplastic large T-cell lymphoma (186 [9%] of 1979 patients), mature T-cell lymphoma, not otherwise specified (163 [8%] of 1979), angioimmunoblastic T-cell lymphoma (123 [6%] of 1979 patients), and ALK-positive anaplastic large T-cell lymphoma (73 [4%] of 1979 patients). The observed proportion of people with adult T-cell leukaemia or lymphoma was higher in Peru (158 [39%] of 414 patients; p<0·0001) and Colombia (17 [29%] of 58 patients; p=0·011), whereas the percentage for extranodal natural killer T-cell lymphoma was higher in Central America and the Caribbean (105 [41%] of 255 patients; p<0·0001) and Mexico (22 [31%] of 70 patients; p<0·0001). With a median follow-up of 36 months (IQR 12-60) in the analytical cohort, we observed 674 deaths, and 3-year overall survival was 40% (95% CI 38-44). ALK-positive anaplastic large T-cell lymphoma had the highest survival outcomes, with 11 deaths and a 3-year overall survival of 77% (95% CI 66-90), followed by ALK-negative anaplastic large T-cell lymphoma (52 deaths and 3-year overall survival of 55%, 95% CI 46-65) and extranodal natural killer T-cell lymphoma (108 deaths and 3-year overall survival of 48%, 95% CI 42-56). The use of CHOEP (cyclophosphamide, doxorubicin, etoposide, vincristine, and prednisone) or EPOCH (etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin) was associated with superior 3-year overall survival compared with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) among patients with ALK-negative anaplastic large T-cell lymphoma (20 deaths; 67%, 95% CI 56-81 vs 16 deaths; 41%, 26-65; p=0·018) and adult T-cell leukaemia or lymphoma (45 deaths; 20%, 11-38 vs 100 deaths; 18%, 12-27; p=0·0087), but not for all other subtypes.

INTERPRETATION

Our study underscores the unique epidemiological profile of peripheral T-cell lymphoma in Latin America, with a high prevalence of adult T-cell leukaemia or lymphoma and extranodal natural killer T-cell lymphoma. These findings present a crucial opportunity to prioritise clinical trials on these rare subtypes of peripheral T-cell lymphoma by integrating Latin American countries into global research. However, our findings require further validation in robust epidemiological studies.

FUNDING

American Society of Hematology Harold Amos Medical Faculty Development Program Award and the Robert A Winn Diversity in Clinical Trials Program Award.

TRANSLATIONS

For the Portuguese and Spanish translations of the abstract see Supplementary Materials section.

Update on T-Cell Lymphoma Epidemiology

PURPOSE OF REVIEW

T-cell lymphomas (TCLs) are a group of rare subtypes of non-Hodgkin lymphoma derived from mature T-lymphocytes. Recent updates in lymphoma classification based on the cell-of-origin pathogenesis have shed new light on TCL epidemiology and outcomes. Contemporary regional consortia and international studies, including those conducted recently in Asia and South America, have provided an updated delineation of the major subtypes across various global regions.

RECENT FINDINGS

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), remains the most common subtype globally except in Asia, where extra-nodal NK-T cell lymphoma (ENKTL) has emerged as the most prevalent. Angioimmunoblastic T-cell lymphoma (AITL) is the second most common subtype globally except in South America where its incidence falls behind adult T-cell leukemia/lymphoma (ATLL) and ENKTL. ALK-negative anaplastic large cell lymphoma (ALCL) has been recognized as the second most common subtype in some parts of South America. Studies on the newly classified breast implant-associated ALCL (BIA-ALCL) are beginning to reveal its distribution and risk factors. Deciphering the epidemiology of TCLs is a challenging endeavor due to the rarity of these entities and ongoing refinement in classification. Collaborative efforts on prospective registries based on the most current WHO classifications will help capture the true epidemiology of TCL subtypes to better focus resources for diagnostic, prognostic, and therapeutic efforts.

Extranodal NK-/T-cell lymphoma, nasal type: what advances have been made in the last decade?

Extranodal NK-/T-cell lymphoma (ENKTCL) is a rare and highly aggressive malignancy with significant racial and geographic variations worldwide. In addition to the formerly "nasal-type" initial description, these lymphomas are predominantly extranodal in origin and typically cause vascular damage and tissue destruction, and although not fully understood, Epstein-Barr virus (EBV) has an important role in its pathogenesis. Initial assessment must include a hematopathology review of representative and viable tumor areas without necrosis for adequate immunohistochemistry studies, including EBV-encoded small RNA (EBER) in situ hybridization (ISH). Positron emission tomography with 18-fluorodeoxyglucose (¹⁸F-FDG-PET/CT) for accurate staging is essential, and most patients will have localized disease (IE/IIE) at diagnosis. Apart from other T-cell malignancies, the best treatment even for localized cases is combined modality therapy (chemotherapy plus radiotherapy) with non-anthracycline-based regimens. For advanced-stage disease, l-asparaginase-containing regimens have shown improved survival, but relapsed and refractory cases have very poor outcomes. Nowadays, even with a better understanding of pathogenic pathways, up-front therapy is completely based on chemotherapy and radiotherapy, and treatment-related mortality is not low. Future strategies targeting signaling pathways and immunotherapy are evolving, but we need to better identify those patients with dismal outcomes in a pre-emptive way. Given the rarity of the disease, international collaborations are urgently needed, and clinical trials are the way to change the future.

Extranodal NK/T cell lymphoma, nasal type: An updated overview

Extranodal NK/T-cell lymphoma, nasal type (ENKTCL-NT) is an aggressive malignancy associated with Epstein-Barr virus infection, with a geographic and racial predilection for some Asian and Latin American countries. ENKTCL-NT manifests as a necrotic process affecting nasal or upper aerodigestive structures and, rarely, extranasal sites such as skin, and the gastrointestinal tract. ENKTCL-NT was characterized by its poor prognosis irrespective of clinical stage and therapy. However, during the last two decades, advances in its clinicopathologic, genetic and molecular characterization have been achieved, as have changes in the chemotherapy regimens that, in combination with radiotherapy, are significantly improving the survival of these patients, especially in initial stages. For these reasons, we present an overview of the historical background of ENKTCL-NT along with an updated review of its potential etiological factors, clinicopathologic and molecular features, as well as its prognostic models, current treatment protocols, and future directions on potential promising therapeutic approaches.

Epidemiology of Hematologic Malignancies in Real-World Settings: Findings From the Hemato-Oncology Latin America Observational Registry Study

PURPOSE

Limited information is available on multiple myeloma (MM), chronic lymphocytic leukemia (CLL), and non-Hodgkin lymphoma (NHL) management in Latin America. The primary objective of the Hemato-Oncology Latin America (HOLA) study was to describe patient characteristics and treatment patterns of Latin American patients with MM, CLL, and NHL.

METHODS

This study was a multicenter, retrospective, medical chart review of patients with MM, CLL, and NHL in Latin America identified between January 1, 2006, and December 31, 2015. Included were adults with at least 1 year of follow-up (except in cases of death within 1 year of diagnosis) treated at 30 oncology hospitals (Argentina, 5; Brazil, 9; Chile, 1; Colombia, 5; Mexico, 6; Panama/Guatemala, 4).

RESULTS

Of 5,140 patients, 2,967 (57.7%) had NHL, 1,518 (29.5%) MM, and 655 (12.7%) CLL. Median follow-up was 2.2 years for MM, 3.0 years for CLL, and 2.2 years for NHL, and approximately 26% died during the study observation period. Most patients had at least one comorbidity at diagnosis. The most frequent induction regimen was thalidomide-based chemotherapy for MM and chlorambucil with or without prednisone for CLL. Most patients with NHL had diffuse large B-cell lymphoma (DLBCL; 49.1%) or follicular lymphoma (FL; 19.5%). The majority of patients with DLBCL or FL received rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone.

CONCLUSION

The HOLA study generated an unprecedented level of high-quality, real-world evidence on characteristics and treatment patterns of patients with hematologic malignancies. Regional disparities in patient characteristics may reflect differences in ethnoracial identity and level of access to care. These data provide needed real-world evidence to understand the disease landscape in Latin America and may be used to inform clinical and health policy decision making.

Extranodal NK/T-Cell Lymphoma, Nasal Type in Guatemala: An 86-Case Series Emphasizing Clinical Presentation and Microscopic Characteristics

Extranodal NK/T-cell lymphoma, nasal type (ENKTCL-NT) is a lymphoid malignancy that mainly affects the nasopharynx and is associated with the Epstein-Barr virus (EBV). Increased incidence is seen in some Latin American and Asian countries. In this study, we describe a case series of 86 Guatemalan patients with ENKTCL-NT from a single diagnostic head and neck center. We emphasize the distinctive clinical, microscopic, and immunohistochemical (IHC) features, as well as EBV positivity by in situ hybridization (ISH). Most of the patients (90.6%) were of Mayan descent and low socioeconomic status (SES). Males were more often affected than females, comprising 68.3% of cases. Patient age ranged from 8 to 71, with a mean of 34.7 years. All cases arose in the upper aerodigestive tract and mainly presented as a rapidly progressive, necrotizing midfacial process affecting the nasal, nasopharyngeal, sinonasal, palatal, and oropharyngeal structures. Microscopically, ENKTCL-NT showed a diffuse polymorphic and atypical lymphoid infiltrate. Angiocentric and angiodestructive growth patterns were present with associated necrosis. Peripheral hyaline necrosis of blood vessels was a histologic hallmark. The ISH and IHC profiles included positivity of EBV, LCA, CD3, CD45RO, CD30 (focal in 39.2%), granzyme-B, TIA-1, perforin (in 82.3%), and CD56 (in 83.7%). CD20 was negative, and the Ki-67 index ranged from 70 to 90%. In Guatemala, this lymphoma is strongly associated with people of low SES and indigenous ethnicity. When affected, the palatal mucosa provides the best site to obtain a representative biopsy. Since ENKTCL-NT is highly aggressive, it is extremely important to recognize the spectrum of clinical presentations and microscopic features in order to avoid misdiagnosis and treatment delay.

Molecular and Genomic Landscape of Peripheral T-Cell Lymphoma

Peripheral T-cell lymphoma (PTCL) is an uncommon group of lymphoma covering a diverse spectrum of entities. Little was known regarding the molecular and genomic landscapes of these diseases until recently but the knowledge is still quite spotty with many rarer types of PTCL remain largely unexplored. In this chapter, the recent findings from gene expression profiling (GEP) studies, including profiling data on microRNA, where available, will be presented with emphasis on the implication on molecular diagnosis, prognostication, and the identification of new entities (PTCL-GATA3 and PTCL-TBX21) in the PTCL-NOS group. Recent studies using next-generation sequencing have unraveled the mutational landscape in a number of PTCL entities leading to a marked improvement in the understanding of their pathogenesis and biology. While many mutations are shared among PTCL entities, the frequency varies and certain mutations are quite unique to a specific entity. For example, TET2 is often mutated but this is particularly frequent (70-80%) in angioimmunoblastic T-cell lymphoma (AITL) and IDH2 R172 mutations appear to be unique for AITL. In general, chromatin modifiers and molecular components in the CD28/T-cell receptor signaling pathways are frequently mutated. The major findings will be summarized in this chapter correlating with GEP data and clinical features where appropriate. The mutational landscape of cutaneous T-cell lymphoma, specifically on mycosis fungoides and Sezary syndrome, will also be discussed.

Adult T-cell leukemia/lymphoma in South and Central America and the Caribbean: systematic search and review

Adult T-cell leukemia/lymphoma (ATL) is caused by the human T-cell lymphotropic virus type 1 (HTLV-1) which is endemic in countries of Caribbean and Central and South America. We performed a systematic search and review to identify publications on ATL in these countries to verify if this disease was getting recognition in these regions as well as the characteristics of the observed cases. The median age of 49.4 years was lower than that referred to in Japan. According to our findings in most Brazilian states and in some other countries, ATL is not being recognized and should be strongly considered in the differential diagnosis of T-cell leukemias/lymphomas. Failure to identify these cases may be due to the unsystematic realization of serology for HTLV-1 and phenotypic identification of non-Hodgkin lymphomas that may result from lack of resources. Detection of ATL cases has been more feasible with cooperation from foreign research centers. A huge effort should be made to improve the surveillance system for ATL diagnosis in most of the South- and Central-American and Caribbean countries, and this attitude should be embraced by public organs to support health professionals in this important task.

Non-Hodgkin lymphoma in the Far East: review of 730 cases from the international non-Hodgkin lymphoma classification project

Large and systematic studies of non-Hodgkin lymphoma (NHL) in the Far East (FE) with good comparative data are scarce in the literature. In this study, five expert hematopathologists classified 730 consecutive cases of newly-diagnosed NHL from four sites in the FE (excluding Japan) using the World Health Organization classification. The results were compared to 399 cases from North America (NA). We found a significantly higher male to female ratio in the FE compared to NA (1.7 versus 1.1; p < 0.05). The median ages of patients with low-grade (LG) and high-grade (HG) B-NHL in the FE (58 and 51 years, respectively) were significantly lower than in NA (64 and 68 years, respectively). The FE had a significantly lower relative frequency of B-NHL and a higher frequency of T-NHL (82 vs. 18 %) compared to NA (90.5 vs. 9.5 %). Among mature B cell lymphomas, the FE had a significantly higher relative frequency of HG B-NHL (54.8 %) and a lower frequency of LG B-NHL (27.2 %) than NA (34.3 and 56.1 %, respectively). Diffuse large B cell lymphoma was more common in the FE (49.4 %) compared to NA (29.3 %), whereas the relative frequency of follicular lymphoma was lower in the FE (9.4 %) compared to NA (33.6 %). Among T-NHL, nasal NK/T cell NHL was more frequent in the FE (5.2 %) compared to NA (0 %). Peripheral T cell lymphoma was also more common in the FE (9.1 %) than in NA (5.3 %). Further epidemiologic studies are needed to better understand the pathobiology of these differences.

Nasal NK/T-Cell Lymphoma. A Comparative Analysis of a Mexican Population with the Other Populations of Latin-America

Nasal natural killer/T-cell lymphoma (nasal NKTCL), is a rare presentation of extranodal lymphoma in North-America and Europe, but in some countries, as China and Korea, nasal NKTCL occurred in 20 to 46 % of T-cell lymphomas. Some studies, analyzing the incidence in Latin-America, observed some differences between the various populations. However, this comparison included Argentina and Chile, Peru, and other Latin-America but not the Mexico. Thus, we performed a retrospective analysis of the patients diagnosed and treated as nasal, NKTCL, in our institution that is an academic tertiary national reference hospital of Mexico.

From 1988 to 2014, we diagnosed and treated 14,816 cases of non-Hodgkin’s lymphoma, 10,957 (73%) were of B-cell histology and 3822 (26%) were of T-cell histology. Nasal, NKTCL, was the most frequent of the T-cell histology: 40%. We compared our results with those of other countries and observed that nasal, NKTCL have a small number of cases in North-America, and in some countries of Latin-America, as Argentina, Brazil, and Chile. However, the number of NKTCL cases found in Mexico was similar to that found in Guatemala and Peru, and also in China and Korea. Our study suggests that this neoplasm could have a racial basis, but environmental factors should also be considered.

Classification of non-Hodgkin lymphoma in Central and South America: a review of 1028 cases

The distribution of non-Hodgkin lymphoma (NHL) subtypes differs around the world but a systematic study of Latin America has not been done. Therefore, we evaluated the relative frequencies of NHL subtypes in Central and South America (CSA). Five expert hematopathologists classified consecutive cases of NHL from 5 CSA countries using the WHO classification and compared them to 400 cases from North America (NA). Among the 1028 CSA cases, the proportions of B- and T-cell NHL and the sex distribution were similar to NA. However, the median age of B-cell NHL in CSA (59 years) was significantly lower than in NA (66 years; P < .0001). The distribution of high-grade (52.9%) and low-grade (47.1%) mature B-cell NHL in CSA was also significantly different from NA (37.5% and 62.5%; P < .0001). Diffuse large B-cell lymphoma was more common in CSA (40%) than in NA (29.2%; P < .0001), whereas the frequency of follicular lymphoma was similar in Argentina (34.1%) and NA (33.8%), and higher than the rest of CSA (17%; P < .001). Extranodal NK/T-cell NHL was also more common in CSA (P < .0001). Our study provides new objective evidence that the distribution of NHL subtypes varies significantly by geographic region and should prompt epidemiologic studies to explain these differences.