Management of advanced NK/T-cell lymphoma

Allogeneic Hematopoietic Stem Cell Transplantation in Extranodal Natural Killer/T-cell Lymphoma

Objective

Extranodal NK/T-cell lymphoma (ENKL) is aggressive and resistant to chemotherapy and radiotherapy. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for high-risk lymphomas owing to its associated graft-versus-lymphoma (GVL) effect. However, its application to ENKL is limited. We aim to summarize the characteristics of allo-HSCT for ENKL and, more importantly, evaluate whether allo-HSCT could offer any benefits for ENKL.

Materials and Methods

A systematic review and data analysis were performed to evaluate the performance of allo-HSCT in the treatment of ENKL using studies obtained from PubMed, Medline, and Embase from January 2000 to December 2019 in the English language.

Results

A total of 136 cases from 17 eligible publications were included in this study. It was found that after allo-HSCT, with an average follow-up time of 34 months (range: 1-121 months), 37.5% (52) of 136 patients had acute graft-versus-host disease (GVHD) and 31.6% (43) had chronic GVHD. Furthermore, 35.3% (48) of the patients were reported to have relapsed, but 2 of those relapsed only locally and achieved complete remission (CR) again with additional irradiation, chemotherapy, and donor lymphocyte infusions for one and rapid tapering and discontinuation of cyclosporine for the other, earning more than one year of extra survival. Finally, of the 136 patients, 51.5% (70) died because of primary disease progression (42.9%), infection (20.0%), GVHD (11.4%), organ failure (7.1%), hemorrhage (4.3%), and other causes (not specified/unknown) (14.3%).

Conclusion

Allo-HSCT may be a treatment option for advanced or relapsed/refractory ENKL, but its role still requires more rigorous future studies.

Overview of Cutaneous T-Cell Lymphomas

Non-Hodgkin's lymphoma (NHL) encompasses a diverse collection of systemic and primary cutaneous lymphomas. Cutaneous T-cell lymphomas (CTCLs) represent about 13% of all NHLs, which are further subdivided into a heterogeneous group with vastly different presentations and histologic features. Diagnosis requires integration of clinical, pathologic, and molecular features. Among CTCLs, mycosis fungoides and Sézary syndrome are the most prevalent. Treatment is aimed at limiting morbidity and halting disease progression. Hematopoietic stem cell transplantation is the only therapy with curative intent.

Natural killer/T-cell lymphoma invading the orbit and globe

Natural killer/T-cell lymphomas are extremely rare and carry high mortality rates. Epidemiologically, these cancers tend to affect mainly Asian and South American patients and are associated with Epstein-Barr virus seropositivity. This report details a 78-year-old Vietnamese woman who presented initially with vitritis of unknown cause, but later developed proptosis and conjunctival involvement as her disease spread. Biopsies of the orbit, ethmoid sinus, and conjunctiva were found to be significant for natural killer/T-cell lymphoma. The case highlights the diagnostic difficulty of this tumor given its rarity and ability to mimic other disorders.

Clinicopathologic Characterization of Aggressive Natural Killer Cell Leukemia Involving Different Tissue Sites

Aggressive natural killer cell leukemia (ANKL) is a rare disease with an extremely aggressive clinical course. The etiology of ANKL is unclear with few genetic/epigenetic aberrations described to date. Moreover, misdiagnosis of ANKL is a frequent problem. Clinicopathologic characteristics of 35 retrospective cases of ANKL were investigated with the aim of improving diagnosis and to find the genetic/epigenetic aberrations associated with ANKL etiology. Because of the relatively low number of leukemic cells in the peripheral blood and bone marrow, diagnosis of ANKL can be missed; therefore, it is important to perform biopsy on solid tissues, if necessary. We describe the pathology of ANKL in the lymph nodes, bone marrow, spleen, liver, and skin, with focus on diagnosis and differentiated diagnosis. We observed young male predominance in our cohort, and the clinical course was more aggressive than reported previously. Low lactate dehydrogenase (<712 IU/L), chemotherapy or L-asparaginase administration were found to be associated with more favorable outcomes. SH2 domains of STAT5B and STAT3 also were screened for the presence of activating mutations. Moreover, CpG island methylation status of HACE1, a candidate tumor-suppressor gene, was determined in ANKL samples. We observed activating STAT5B mutations (1/5) and hypermethylation of HACE1 (3/4) in ANKL cases, suggesting that these aberrations may contribute to ANKL pathogenesis.

Clonal deleted latent membrane protein 1 variants of Epstein-Barr virus are predominant in European extranodal NK/T lymphomas and disappear during successful treatment

Extranodal natural killer/T-cell lymphomas (NK/TL), rare in Europe, are Epstein-Barr virus (EBV) associated lymphomas with poor outcomes. Here, we determined the virus type and analyzed the EBV latent membrane protein-1 (LMP1) gene sequence in NK/TL from French patients. Six clones of viral LMP1 were sequenced by Sanger technology in blood from 13 patients before treatment with an l-asparaginase based regimen and, for 8 of them, throughout the treatment. Blood LMP1 sequences from 21 patients without any known malignancy were tested as controls. EBV Type A was identified for 11/13 patients and for all controls. Before treatment, a clonal LMP1 gene containing a 30 bp deletion (del30) was found in 46.1% of NK/TL and only in 4.8% of controls. Treatment was less effective in these patients who died more rapidly than the others. Patients with a deleted strain evolving toward a wild-type strain during treatment reached complete remission. The LMP1 gene was sequenced by highly sensitive next-generation sequencing technology in five NK/TL nasopharyngeal biopsies, two of them originating from the previous patients. Del30 was present in 100% of the biopsies; two viruses at least coexisted in three biopsies. These results suggest that del30 may be associated with poor prognosis NK/TL and that strain evolution could be used as a potential marker to monitor treatment.

A TNM Staging System for Nasal NK/T-Cell Lymphoma

Ann Arbor stage has limited utility in the prognostication and treatment decision making in patients with NK/T-cell lymphoma (NKTCL), as NKTCL is almost exclusively extranodal and the majority is localized at presentation for which radiotherapy is the most important treatment and local invasiveness is the most important prognostic factor. In this study, we attempted to establish a TNM (Tumor-Node-Metastasis) staging system for nasal NKTCL (N-NKTCL). The staging rules of other head and neck cancers were used as reference along with the data of our 271 eligible patients. The primary tumor was classified into T1 to T4, and cervical lymph node metastasis was classified into N0 to N2 according to the extent of involvement. Any lesions outside the head and neck were classified as M1. N-NKTCL thereby was classified into four stages: stage I comprised T1-2N0M0; stage II comprised T1-2N1M0 and T3N0M0; stage III comprised T3N1M0, T1-3N2M0, and T4N0-2M0; and stage IV comprised TanyNanyM1. This staging system showed excellent performance in prognosticating survival. In the current series, the 5-year survival rates of patients with stages I, II, III, and IV N-NKTCL were 92%, 64%, 23%, and 0, respectively. Moreover, the predictive value of several currently used factors was abrogated in the presence of the TNM stage. The TNM staging system is highly effective in stratifying tumor burden and survival risk, which may have significant implications in the treatment decision making for patients with N-NKTCL.

Primary cutaneous natural killer/T-cell lymphoma of the nasal type: a report of 4 cases in North American patients

The "nasal" type of primary cutaneous lymphoma with natural killer/T-cell differentiation is rarely encountered outside Asia. The authors herein document 4 cases in White, North American individuals between the ages of 39 and 73 years. Their skin lesions were located on the legs in 2 cases, and they were multifocal in the other 2 patients. Microscopically, each neoplasm manifested as a dense infiltrate of cytologically aberrant lymphocytes in the dermis and subcutis. The lesional cells were angiocentric, with associated infarctive-type necrosis of the surrounding tissue. All tumors were labeled for CD3 and CD56; 3 also expressed T-cell intracellular antigen 1. Chromogenic in situ hybridization was intensely reactive for Epstein-Barr virus-encoded ribonucleic acid in each case. All patients died of their tumors or were likely to do so. The pathologic differential diagnosis of "nasal-type" natural killer/T-cell lymphoma in the skin principally centers on γ-δ T-cell lymphoma and subcutaneous panniculitis-like T-cell lymphoma. Integrated analysis of histologic, immunohistochemical, genotypic, and in situ hybridization data is necessary to separate these entities from one another.