Successful treatment with Erwinia L-asparaginase for recurrent natural killer/T cell lymphoma

Extranodal natural killer/T-cell lymphoma: current concepts in biology and treatment

Natural killer/T-cell (NK/T) lymphomas represent a group of rare tumors of NK and NK-T cells. The World Health Organization classifies NK-cell tumors into three types, extranodal NK/T-cell lymphomas (ENKL, nasal and non-nasal), NK-cell leukemias, and a blastic variant (CD4-positive, CD56-positive hematodermic neoplasms). We focus our review to the current concepts in biology and treatment of ENKL. Though considerable advances have been made in our understanding of NK-cell biology, malignant transformation including the role of Epstein-Barr virus, and prognosis, the rare nature of ENKL and its heterogeneity limit the ability to standardize therapy. Radiotherapy is fundamental to treatment of early-stage disease with a role for chemoradiotherapy among high-risk patients. The clinical course of advanced disease is highly aggressive with frequent chemotherapy resistance and a poor prognosis. Therapeutic approaches to advanced-stage or relapsed and refractory disease, including the appropriate sequence of chemotherapy, combined modality therapy, and stem cell transplantation is not well-established. International and multicenter clinical trials are needed for this rare and aggressive disease.

Prognostic factors for mature natural killer (NK) cell neoplasms: aggressive NK cell leukemia and extranodal NK cell lymphoma, nasal type

BACKGROUND

Patients with natural killer (NK) cell neoplasms, aggressive NK cell leukemia (ANKL) and extranodal NK cell lymphoma, nasal type (ENKL), have poor outcome. Both diseases show a spectrum and the boundary of them remains unclear. The purpose of this study is to draw a prognostic model of total NK cell neoplasms.

PATIENTS AND METHODS

We retrospectively analyzed 172 patients (22 with ANKL and 150 with ENKL). The ENKLs consisted of 123 nasal and 27 extranasal (16 cutaneous, 9 hepatosplenic, 1 intestinal and 1 nodal) lymphomas.

RESULTS

Complete remission rate for ENKL was 73% in stage I, but 15% in stage IV, which was consistent with that for ANKL (18%). The prognosis of ENKL was better than that of ANKL (median survival 10 versus 1.9 months, P < 0.0001) but was comparable when restricted to stage IV cases (4.0 months, P = 0.16). Multivariate analysis showed that four factors (non-nasal type, stage, performance status and numbers of extranodal involvement) were significant prognostic factors. Using these four variables, an NK prognostic index was successfully constructed. Four-year overall survival of patients with zero, one, two and three or four adverse factors were 55%, 33%, 15% and 6%, respectively.

CONCLUSION

The current prognostic model successfully stratified patients with NK cell neoplasms with different outcomes.

Advances in the management and monitoring of extranodal NK/T-cell lymphoma, nasal type

Extranodal natural killer (NK)/T-cell lymphoma, nasal type, has a unique geographic distribution. Its pathology is characterized by marked angio-invasion and tissue necrosis. A typical NK-cell phenotype is usually present: CD2(+), CD3 epsilon+, CD56(+), cytotoxic molecules+ and Epstein-Barr virus (EBV)+. Magnetic Resonance Imaging helps to clearly define the local involvement. Positron Emission Tomography helps to demonstrate system spread. Various prognostic variables (International Prognostic Index or the Korean Prognostic Index) should be documented. This may include quantification of plasma EBV DNA. For localized nasal disease, radiotherapy is important, although chemotherapy is often added. Sustainable remission is observed in over half of these patients. For extra-nasal or disseminated disease, systemic chemotherapy becomes the mainstay and the prognosis is usually poor. Doxorubicin-containing regimens are not entirely satisfactory and L-asparaginase containing regimens are being investigated. Patients with poor prognostic features may be considered for an early autologous haematopoietic stem cell transplant. Allogeneic transplantation is efficacious but is associated with high transplant-related mortality.

L-asparaginase-based treatment of 15 western patients with extranodal NK/T-cell lymphoma and leukemia and a review of the literature

BACKGROUND

Extranodal natural killer (NK)/T-cell lymphoma, nasal type, and aggressive NK-cell leukemia are highly aggressive diseases with a poor outcome.

PATIENTS AND METHODS

We report a multicentric French retrospective study of 15 patients with relapsed, refractory, or disseminated disease, treated with L-asparaginase-containing regimens in seven French centers. Thirteen patients were in relapse and/or refractory and 10 patients were at stage IV.

RESULTS

All but two of the patients had an objective response to L-asparaginase-based treatment. Seven patients reached complete remission and only two relapsed.

CONCLUSION

These data, although retrospective, confirm the excellent activity of L-asparaginase-containing regimens in refractory extranodal NK/T-cell lymphoma and aggressive NK-cell leukemia. Therefore, L-asparaginase-based regimen should be considered as a salvage treatment, especially for patients with disseminated disease. First-line L-asparaginase combination therapy for extranodal NK/T-cell lymphoma and aggressive NK-cell leukemia should be tested in prospective trials.

Extranodal NK/T-cell lymphoma: diagnosis and treatment cues

Extranodal NK/T-cell lymphoma, nasal type (ENKL) is mostly endemic to East Asia. It predominantly occurs in the nasal or paranasal areas and less frequently in the skin. Most of the tumours show NK-cell, but rarely T-cell, phenotypes. The Epstein-Barr virus (EBV) genome can be usually detected in lymphoma cells. Geographic localization of ENKL matches the endemic distribution of EBV, suggesting that EBV plays an important role in lymphomagenesis. Originally, NK-cell and T-cell types were believed to present the same clinicopathologic characteristics, but recent data suggest more aggressive characteristics for the NK-cell phenotype. Although ENKL is sensitive to radiotherapy, it shows a poorer response to chemotherapeutic agents than other lymphomas due to expression of p-glycoprotein. Therefore, new therapeutic approaches must be considered. Several new clinical trials are now being conducted in East Asia.