Treatment of adult T-cell leukemia-lymphoma by CHOP followed by therapy with antinucleosides, alpha interferon and oral etoposide

Stem cell therapy for HTLV-1 induced adult T-cell leukemia/lymphoma (ATLL): A comprehensive review

Adult T-cell leukemia/lymphoma (ATLL) is a rare and aggressive form of cancer associated with human T-cell lymphotropic virus type 1 (HTLV-1) infection. The emerging field of stem cell therapies for ATLL is discussed, highlighting the potential of hematopoietic stem cell transplantation (HSCT) and genetically modified stem cells. HSCT aims to eradicate malignant T-cells and restore a functional immune system through the infusion of healthy donor stem cells. Genetically modified stem cells show promise in enhancing their ability to target and eliminate ATLL cells. The article presents insights from preclinical studies and limited clinical trials, emphasizing the need for further research to establish the safety, efficacy, and long-term outcomes of stem cell therapies for ATLL and challenges associated with these innovative approaches are also explored. Overall, stem cell therapies hold significant potential in revolutionizing ATLL treatment, and ongoing clinical trials aim to determine their benefits in larger patient populations.

Chapter XX Antiviral Treatment and Cancer Control

Hepatitis B virus (HBV), hepatitis C virus (HCV), human papilloma virus (HPV), Epstein-Barr virus (EBV), human T-cell lymphotropic virus type 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), and Merkel cell polyomavirus (MCV) contribute to about 10-15% global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. However, a more proactive approach would be the use of antiviral treatment to suppress or eliminate viral infections to prevent the occurrence of cancer in the first place. Antiviral treatments against chronic HBV and HCV infection have achieved this goal, with significant reduction in the incidence of hepatocellular carcinoma in treated patients. Antiviral treatments for EBV, KSHV, and HTLV-1 had limited success in treating refractory EBV-associated lymphoma and post-transplant lymphoproliferative disorder, KSHV-associated Kaposi's sarcoma in AIDS patients, and HTLV-1-associated acute, chronic, and smoldering subtypes of adult T-cell lymphoma, respectively. Therapeutic HPV vaccine and RNA interference-based therapies for treating HPV-associated infection or cervical cancers also showed some encouraging results. Taken together, antiviral therapies have yielded promising results in cancer prevention and treatment. More large-scale studies in a real-world setting are necessary to confirm the efficacy of antiviral therapy. Further investigation for more effective and convenient antiviral regimens warrants more attention.

Management of Lymphomas: Consensus Document 2018 by an Indian Expert Group

The clinical course of lymphoma depends on the indolent or aggressive nature of the disease. Hence, the optimal management of lymphoma needs a correct diagnosis and classification as B cell, T-cell or natural killer (NK)/T-cell as well as indolent or high-grade type lymphoma. The current consensus statement, developed by experts in the field across India, is intended to help healthcare professionals manage lymphomas in adults over 18 years of age. However, it should be noted that the information provided may not be appropriate to all patients and individual patient circumstances may dictate alternative approaches. The consensus statement discusses the diagnosis, staging and prognosis applicable to all subtypes of lymphoma, and detailed treatment regimens for specific entities of lymphoma including diffuse large B-cell lymphoma, Hodgkin's lymphoma, follicular lymphoma, T-cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, Burkitt's lymphoma, and anaplastic large cell lymphoma.

Overview of Targeted Therapies for Adult T-Cell Leukemia/Lymphoma

Adult T-Cell Leukemia/lymphoma (ATL) is the first human malignancy associated with a chronic infection by a retrovirus, the human T-cell lymphotropic virus type I (HTLV-I). ATL occurs, after a long latency period, only in about 5% of 10-20 millions infected individuals. ATL has a dismal prognosis with a median survival of less than 1 year, mainly due to its resistance to chemotherapy and to a profound immunosuppression. The viral oncoprotein, Tax, plays a major role in ATL oncogenic transformation by interfering with cell proliferation, cell cycle, apoptosis, and DNA repair. The diversity in ATL clinical features and prognosis led to Shimoyama classification of ATL into four clinical subtypes (acute, lymphoma, chronic, and smoldering) requiring different therapeutic strategies. Clinical trials, mainly conducted in Japan, demonstrated that combination of chemotherapy could induce acceptable response rate in the lymphoma subtype but not in acute ATL. However, long-term prognosis remains poor for both subtypes, due to a high relapse rate. Similarly, whether managed by a watchful waiting or treated with chemotherapy, the indolent forms (smoldering and chronic) have a poor long-term outcome. An international meta-analysis showed improved survival in the leukemic subtypes of ATL (chronic, smoldering as well as a subset of the acute subtype) with the use of two antiviral agents, zidovudine and interferon-alpha, and accordingly, this combination should be considered the standard first-line treatment in this context. ATL patients with lymphoma subtype benefit from induction chemotherapy, given simultaneously or sequentially with an antiviral combination of zidovudine and interferon-alpha. Allogeneic hematopoietic stem cells transplantation remains a promising and potentially curative approach but is limited to a small number of patients. Novel drugs such as arsenic trioxide in combination with interferon-alpha or monoclonal antibodies such as anti-CXCR4 have shown promising results and warrant further investigation.

Autologous stem cell transplantation in first complete remission may not extend progression-free survival in patients with peripheral T cell lymphomas

Patients with peripheral T cell lymphomas (PTCL) generally have a poor prognosis when treated with conventional chemotherapy. Consolidation with autologous stem cell transplantation (ASCT) has been reported to improve progression-free survival. However, these studies have not compared consolidative ASCT with active observation in patients with PTCL achieving first complete remission (CR1) following induction chemotherapy. We conducted a retrospective analysis of PTCL patients treated at the University of Pennsylvania between 1/1/2007 and 12/31/2014. Patients with cutaneous T cell lymphoma, concurrent B cell lymphomas, and anaplastic lymphoma kinase-positive anaplastic large cell lymphoma (ALK-positive ALCL) were excluded from the study. We compared progression-free survival for patients who underwent ASCT in CR1 following CHOP-like induction regimens and patients who underwent active observation during CR1. 48 patients met all inclusion and exclusion criteria and underwent either active observation (28 patients) or consolidative ASCT (20 patients) in CR1. The 1-year cumulative incidence of relapse in the observation and ASCT groups was 50% (95% confidence interval [CI]: 30-67%) and 46% (95% CI: 23-67%), respectively (P = 0.55). Median progression-free survival in the observation and ASCT groups was 15.8 and 12.8 months, respectively (log rank, P = 0.79). Estimated 3-year progression-free survival in the observation and ASCT groups was 37 and 41%, respectively. In conclusion, for PTCL patients achieving CR1 following CHOP-like induction chemotherapy, ASCT does not appear to improve progression-free survival compared to active observation. This finding should be confirmed in a larger, prospective study. Am. J. Hematol. 91:672-676, 2016. © 2016 Wiley Periodicals, Inc.

Retrospective study of a cohort of adult patients with hematological malignancies in a tropical area

AIM: To review the characteristics of hematological malignancies in tropical areas, and to focus on the specific difficulties regarding their management.

METHODS: This is a retrospective narrative review of cases of patients with hematological malignancies. All medical files of patients with malignant disease whose treatment was coordinated by the Hemato-Oncology service of the Cayenne Hospital in French Guiana between the 1^st of January 2010 and the 31^st of December 2012 were reviewed. Clinical data were extracted from the medical files and included: Demographic data, comorbidities, serological status for human immunodeficiency virus, human T-lymphotropic virus 1 (HTLV1), hepatitis B virus and hepatitis C virus infections, cytology and pathology diagnoses, disease extension, treatment, organization of disease management, and follow-up. The subgroup of patients with hematological malignancies and virus-related malignancies were reviewed. Cases involving patients with Kaposi sarcoma, and information on solid tumor occurrence in virus-infected patients in the whole patient population were included. Since the data were rendered anonymous, no informed consent was obtained from the patients for this retrospective analysis. Data were compiled using EXCEL^® software, and the data presentation is descriptive only. The references search was guided by the nature of the data and discussion.

RESULTS: In total, the clinical files of 594 patients (pts) were reviewed. Hematological malignancies were observed in 87 patients, and Kaposi sarcoma in 2 patients. In total, 70 patients had a viral infection, and 34 of these also had hematological malignancies. The hematological diagnoses were: Multiple myeloma in 27 pts, lymphoma (L) in 43 pts, myeloproliferative disorders in 17 pts and Kaposi sarcoma in two patients. The spectrum of non-Hodgkin lymphomas (NHL) was: Burkitt L (1 pt), follicular L (5 pts), chronic lymphocytic leukemia (5 pts), high-grade NHL (9 pts), mucosa-associated lymphoid tissue NHL (4 pts), T-cell lymphoma (4 pts), Adult T-cell lymphoma-leukemia (ATL)/lymphoma/leukemia (12 pts); three patients had Hodgkin disease. The spectrum of myeloproliferative diseases was: Chronic myelogenous leukemia (8 pts), thrombocytemia (5 pts) and acute leukemia (4 pts). There were no polycythemia vera, myelosclerosis, and myelodysplastic diseases. This appears to be due to bias in the recruitment process. The most important observations were: The specificity of HTLV1- related ATL malignancies, and the high incidence of virus infections in patients with hematological malignancies. Further, we noted several limitations regarding the treatment and organization of disease management. These were not related to the health care organization, but were due to a lack of board-certified hemato-oncology specialists, a lack of access to diagnostic tools (e.g., cytogenetic and molecular diagnosis, imaging techniques), the unavailability of radiotherapy, and the physical distance from mainland France. Yet the geography and cultures of the country also contributed to the encountered difficulties. These same limitations are seen in tropical countries with low and intermediate household incomes, but they are amplified by economic, social, and cultural issues. Thus, there is often little access to diagnostic procedures, adequate clinical management, and an unavailability of suitable medical treatments. Programs have been developed to establish centers of excellence, training in pathology diagnosis, and to provide free access to treatment.

CONCLUSION: Management of hematological malignancies in tropical areas requires particular skills regarding specific features of these diseases and in terms of the affected populations, as well as solid public health policies.

Anti-viral treatment and cancer control

Hepatitis B virus (HBV), hepatitis C virus (HCV), human papillomavirus (HPV), and Epstein-Barr virus (EBV) contribute to about 10-15 % global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. However, a more proactive approach would be the use of antiviral treatment to suppress or eliminate viral infections to prevent the occurrence of cancer in the first place. Antiviral treatments against chronic HBV and HCV infections have achieved this goal, with significant reduction in the incidence of hepatocellular carcinoma in treated patients. Antiviral treatments for EBV, Kaposi's sarcoma-associated herpesvirus (KSHV), and human T-cell lymphotropic virus type 1 (HTLV-1) had limited success in treating refractory EBV-associated lymphoma and post-transplant lymphoproliferative disorder, KSHV-associated Kaposi's sarcoma in AIDS patients, and HTLV-1-associated acute, chronic, and smoldering subtypes of adult T-cell lymphoma, respectively. Therapeutic HPV vaccine and RNA-interference-based therapies for treating HPV-associated cervical cancers also showed some encouraging results. Taken together, antiviral therapies have yielded promising results in cancer prevention and treatment. More large-scale studies are necessary to confirm the efficacy of antiviral therapy. Further investigation for more effective and convenient antiviral regimens warrants more attention.

Gemcitabine-based combination regimen in patients with peripheral T-cell lymphoma

This study was conducted to evaluate the efficacy and safety of gemcitabine-based combination regimen in patients with peripheral T-cell lymphoma (PTCL). Between May 2007 and August 2011, 26 consecutive patients with PTCL were enrolled in this study. Of these 26 patients, histology was extranodal NK/T-cell lymphoma, nasal type in 14 (53.9 %), peripheral T-cell lymphoma, not otherwise specified in nine (34.6 %), anaplastic large cell lymphoma, ALK negative in three (11.5 %). The majority of patients had newly diagnosed (65.4 %) and advanced (80.8 %) diseases. Treatment regimen was DIMG (dexamethasone, ifosfamide, methotrexate, and gemcitabine) given to the first 6 patients, and GDP (gemcitabine, dexamethasone, and cisplatin) given to the remaining 20 patients. The median follow-up time was 25 (range 7-60) months. The overall response rate was 88.5 %. Twelve (46.2 %) patients achieved complete remission, 11 (42.3 %) patients achieved partial remission, and 1 (3.8 %) patient had stable disease (SD), two (7.7 %) patients had progressive diseases. The 1- and 2-year progression-free survival rates were 58.7 and 45.9 %, while 1- and 2-year overall survival rates for all patients were 80.6 and 63.7 %, respectively. Adverse events included grade 3 or 4 neutropenia (35.0 %) and thrombocytopenia (15.0 %) from patients treated with GDP. Grade 3 or 4 neutropenia and thrombocytopenia were 100.0 and 66.7 %, respectively, for patients who received DIMG regimen. Our study has demonstrated that the gemcitabine-based combination regimen, especially GDP regimen, is safe and well tolerated with promising clinical activity in patients with PTCLs.

How I treat adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) is an aggressive malignancy of mature activated T cells caused by human T-cell lymphotropic virus type I. ATL carries a bad prognosis because of intrinsic chemoresistance and severe immunosuppression. In acute ATL, Japanese trials demonstrated that although combinations of chemotherapy improved response rate, they failed to achieve a significant impact on survival. Patients with chronic and smoldering ATL have a better prognosis, but long-term survival is poor when these patients are managed with a watchful-waiting policy or with chemotherapy. Recently, a worldwide meta-analysis revealed that the combination of zidovudine and IFN-α is highly effective in the leukemic subtypes of ATL and should be considered as standard first-line therapy in that setting. This combination has changed the natural history of the disease through achievement of significantly improved long-term survival in patients with smoldering and chronic ATL as well as a subset of patients with acute ATL. ATL lymphoma patients still benefit from chemotherapy induction with concurrent or sequential antiretroviral therapy with zidovudine/IFN. To prevent relapse, clinical trials assessing consolidative targeted therapies such as arsenic/IFN combination or novel monoclonal antibodies are needed. Finally, allogeneic BM transplantation should be considered in suitable patients.

Controversies in targeted therapy of adult T cell leukemia/lymphoma: ON target or OFF target effects?

Adult T cell leukemia/lymphoma (ATL) represents an ideal model for targeted therapy because of intrinsic chemo-resistance of ATL cells and the presence of two well identified targets: the HTLV-I retrovirus and the viral oncoprotein Tax. The combination of zidovudine (AZT) and interferon-alpha (IFN) has a dramatic impact on survival of ATL patients. Although the mechanism of action remains unclear, arguments in favor or against a direct antiviral effect will be discussed. Yet, most patients relapse and alternative therapies are mandatory. IFN and arsenic trioxide induce Tax proteolysis, synergize to induce apoptosis in ATL cells and cure Tax-driven ATL in mice through specific targeting of leukemia initiating cell activity. These results provide a biological basis for the clinical success of arsenic/IFN/AZT therapy in ATL patients and suggest that both extinction of viral replication (AZT) and Tax degradation (arsenic/IFN) are needed to cure ATL.

Guidelines for the management of mature T-cell and NK-cell neoplasms (excluding cutaneous T-cell lymphoma)

The peripheral T-cell neoplasms are a biologically and clinically heterogeneous group of rare disorders that result from clonal proliferation of mature post-thymic lymphocytes. Natural killer (NK) cell neoplasms are included in this group. The World Health Organization classification of haemopoietic malignancies has divided this group of disorders into those with predominantly leukaemic (disseminated), nodal, extra-nodal or cutaneous presentation. They usually affect adults and are more commonly reported in males than in females. The median age at diagnosis is 61 years with a range of 17-90 years. Although some subtypes may follow a relatively benign protracted course most have an aggressive clinical behaviour and poor prognosis. Excluding anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL), which has a good outcome, 5-year survival for other nodal and extranodal T-cell lymphomas is about 30%. Most patients present with unfavourable international prognostic index scores (>3) and poor performance status. The rarity of these diseases and the lack of randomized trials mean that there is no consensus about optimal therapy for T- and NK-cell neoplasms and recommendations in this guideline are therefore based on small case series, phase II trials and expert opinion.

Meta-Analysis on the Use of Zidovudine and Interferon-Alfa in Adult T-Cell Leukemia/Lymphoma Showing Improved Survival in the Leukemic Subtypes

Purpose

Human T-cell lymphotropic virus type-I–associated adult T-cell leukemia/lymphoma (ATL) is an aggressive, chemotherapy-resistant malignancy. Multiple small studies using zidovudine (AZT) and interferon-alfa (IFN-α) have shown response in patients with ATL. However, the impact of this innovative antiviral treatment strategy on long-term survival remains undetermined.

Patients and Methods

We report a meta-analysis of antiviral therapy of ATL. Medical records of 254 patients with ATL who were treated in the United States, the United Kingdom, Martinique, and continental France were individually reviewed.

Results

According to Shimoyama classification, there were 116 patients with acute ATL, 18 patients with chronic ATL, 11 patients with smoldering ATL, and 100 patients with ATL lymphoma. In 231 patients with available survival data, first-line therapy was recorded in 207 patients. Five-year overall survival rates were 46% for 75 patients who received first-line antiviral therapy (P = .004), 20% for 77 patients who received first-line chemotherapy, and 12% for 55 patients who received first-line chemotherapy followed by antiviral therapy. Patients with acute, chronic, and smoldering ATL significantly benefited from first-line antiviral therapy, whereas patients with ATL lymphoma experienced a better outcome with chemotherapy. In acute ATL, achievement of complete remission with antiviral therapy resulted in 82% 5-year survival. Antiviral therapy in chronic and smoldering ATL resulted in 100% 5-year survival. Multivariate analysis confirmed that first-line antiviral therapy significantly improves overall survival of patients with ATL (hazard ratio, 0.47; 95% CI, 0.27 to 0.83; P = .021).

Conclusion

These results confirm the high efficacy of AZT and IFN, which should now be considered the gold standard first-line therapy in leukemic subtypes of ATL.

International peripheral T-cell and natural killer/T-cell lymphoma study: pathology findings and clinical outcomes

PURPOSE

Peripheral T-cell lymphoma (PTCL) and natural killer/T-cell lymphoma (NKTCL) are rare and heterogeneous forms of non-Hodgkin's lymphoma (NHL) that, in general, are associated with a poor clinical outcome.

PATIENTS AND METHODS

A cohort of 1,314 cases of PTCL and NKTCL was organized from 22 centers worldwide, consisting of patients with previously untreated PTCL or NKTCL who were diagnosed between 1990 and 2002. Tissue biopsies, immunophenotypic markers, molecular genetic studies, and clinical information from consecutive patients at each site were reviewed by panels of four expert hematopathologists and classified according to the WHO classification.

RESULTS

A diagnosis of PTCL or NKTCL was confirmed in 1,153 (87.8%) of the cases. The most common subtypes were PTCL not otherwise specified (NOS; 25.9%), angioimmunoblastic type (18.5%), NKTCL (10.4%), and adult T-cell leukemia/lymphoma (ATLL; 9.6%). Misclassification occurred in 10.4% of the cases including Hodgkin's lymphoma (3%), B-cell lymphoma (1.4%), unclassifiable lymphoma (2.8%), or a diagnosis other than lymphoma (2.3%). We found marked variation in the frequency of the various subtypes by geographic region. The use of an anthracycline-containing regimen was not associated with an improved outcome in PTCL-NOS or angioimmunoblastic type, but was associated with an improved outcome in anaplastic large-cell lymphoma, ALK positive.

CONCLUSION

The WHO classification is useful for defining subtypes of PTCL and NKTCL. However, expert hematopathology review is important for accurate diagnosis. The clinical outcome for patients with most of these lymphoma subtypes is poor with standard therapies, and novel agents and new modalities are needed to improve survival.

T-cell/NK-cell lymphomas: A review

T-cell neoplasms are a group of heterogeneous neoplasms that present a challenge in management. Accurate diagnosis and classification are necessary for proper treatment. This dilemma is exemplified by continuous upgrading of classification systems in an effort to better understand these diseases. The spectrum of management varies from observation and monitoring to prompt aggressive multimodality treatment to achieve optimal outcomes. Allogeneic transplant has been successful in a minority of cases with the possibility of cure; however this approach is still largely experimental. Molecular studies such as gene expression profiling are expected to offer exciting insight into the biology of these diseases. Novel therapeutic approaches continue to be explored, however will probably require larger clinical trials to establish their utility over the current standard.

Emodin and DHA potently increase arsenic trioxide interferon-alpha-induced cell death of HTLV-I-transformed cells by generation of reactive oxygen species and inhibition of Akt and AP-1

Adult T-cell leukemia (ATL) is an aggressive lymphoproliferative disease of poor clinical prognosis associated with infection by the human T-cell leukemia virus type I (HTLV-I). The use of arsenic trioxide (As2O3) has been shown to effectively treat acute promyelocytic leukemia (APL) with greater than 80% of patients achieving complete remission. The combination of arsenic and interferon has also shown promising results in the treatment of ATL. The requirement for slow dosage increases of arsenic and the time required to achieve a pharmacologic active dose in patients is a major obstacle because median survival of patients with ATL is about 6 months. In this study we report a potent synergistic effect of the combination of arsenic trioxide and interferon alpha (As/IFN-alpha) with emodin and DHA on cell-cycle arrest and cell death of HTLV-I-infected cells. Importantly, we found that clinically achievable doses of DHA and emodin allowed for reduced arsenic concentrations by 100-fold while still remaining highly toxic to tumor cells. Our data provide a rationale for combined use of As/IFN-alpha with emodin and DHA in patients with ATL refractory to conventional therapy.

Synergistic induction of apoptosis in human leukemia T cells by the Akt inhibitor perifosine and etoposide through activation of intrinsic and Fas-mediated extrinsic cell death pathways

Perifosine is an Akt inhibitor displaying strong antineoplastic effects in human tumor cell lines and is currently being tested in phase II clinical trials for treatment of major human cancers. Several recent studies showed the apoptotic effect of perifosine alone or in combination with other anticancer agents. However, this is the first study describing the effects of combining perifosine with the commonly used chemotherapy drug etoposide in cultured human Jurkat T-leukemia cells. Low concentrations of perifosine (5 micromol/L) induced cell death in a synergistic fashion with etoposide if used simultaneously or immediately following exposure to etoposide (posttreatment). The increase in cell death seems to be due to an inactivation of the Akt survival pathway, where treated cells showed a complete dephosphorylation of Akt. Moreover, combined drug-induced Akt deactivation was associated with a parallel decrease in phosphorylation of FoxO1 transcription factor and in expression of antiapoptotic Bcl-xL. Furthermore, the increase in cell death was associated with a specific activation of the caspase-dependent Fas death receptor pathway. These findings might be useful when designing clinical trials where chemotherapy is combined with perifosine for a potential broad use against hematologic malignancies in which the Akt survival pathway is frequently activated.

Human T cell lymphotropic virus-associated leukemia/lymphoma

PURPOSE OF REVIEW

This article summarizes the current pathophysiologic basis for human T cell lymphotropic virus-associated leukemia/lymphoma as well as past, present, and future therapeutic options.

RECENT FINDINGS

New studies have been published on allogeneic stem cell transplantation, arsenic trioxide, and bortezomib for this condition.

SUMMARY

Studies of the molecular biology of human T cell lymphotropic virus-1-induced T cell leukemia/lymphoma have defined a critical role for oncoprotein, Tax, and activation of nuclear factor kappaB transcription pathways, which have provided rational approaches to improved therapy for T cell leukemia/lymphoma as well as a model for other hematopoietic malignancies characterized by nuclear factor kappaB activation.

Therapy of Peripheral T/NK Neoplasms

The mature T/natural killer (NK) lymphoma/leukemias represent 5–15% of all non-Hodgkin lymphoma. These diseases have a geographic variation, with more nodal disease in North America and Europe, including peripheral T cell lymphomas, unspecified, anaplastic large cell lymphoma, and angioimmunoblastic T cell lymphoma; and more extranodal disease in Asia due to Epstein-Barr virus–related nasal NK/T lymphoma and human T-cell leukemia virus (HTLV)-1–associated adult T cell leukemia/lymphoma. The prognosis in most peripheral T/NK neoplasms is poor, with 5-year survival less than 30%. Progress has been slow due to the rarity of the diseases, geographic variation, relative chemoresistance, and lack of randomized trials. There is no consensus about optimal therapy in T/NK neoplasms, and recommendations are based on anecdotal reports, small series, and phase II trials. In this review, topics include the question of CHOP as standard therapy, prognostic factors, disease-adapted therapy, novel approaches, monoclonal antibody therapy, and stem cell transplantation.

T-cell non-Hodgkin lymphoma

T-cell non-Hodgkin lymphomas (NHLs) are uncommon malignancies. The current WHO/EORTC classification recognizes 9 distinct clinicopathologic peripheral T-cell NHLs. These disorders have unique characteristics and require individualized diagnostic and therapeutic strategies. Tremendous progress has been made in recent years in the understanding of the pathogenesis of these disorders. Specific chromosomal translocations and viral infections are now known to be associated with certain lymphomas. In this review, we describe their clinical and pathologic features. We also discuss the use of molecular studies in the diagnostic work-up of T-cell lymphomas. Because of the rarity of these disorders and the lack of well-designed clinical trials, the treatment of peripheral T-cell NHLs is often challenging. Additional studies are required to learn more about the biology of these diseases, which may lead to more optimal and possibly targeted therapies.

Natural history of adult T-cell leukemia/lymphoma and approaches to therapy

After cell-to-cell transmission, HTLV-I increases its viral genome by de novo infection and proliferation of infected cells. Proliferation of infected cells is clonal and persistent in vivo. During the carrier state, infected cells are selected in vivo by the host's immune system, the genetic and epigenetic environment of proviral integration sites, and other factors. In leukemic cells, tax gene expression is frequently impaired by genetic and epigenetic mechanisms. Such loss of Tax expression enables ATL cells to escape the host immune system. On the other hand, ATL cells acquire the ability to proliferate without Tax by intracellular genetic and epigenetic changes. Despite advances in support and the development of novel treatment agents, the prognosis for ATLL remains poor. A number of therapies, however, do appear to improve prognosis compared to CHOP (VEPA). These include interferon-alpha plus zidovudine (probably after 1-2 cycles of CHOP), intensive chemotherapy as in LSG-15 with G-CSF support and Allo-SCT (which includes the potential for cure). Emerging novel approaches include HDAC inhibitors, monoclonal antibodies, and proteasome inhibitors. Comparison between different therapeutic approaches is complicated by the range of natural history of ATLL, different recruitments of naïve-to-therapy, refractory or relapsed patients, and variations in the reporting of outcome that frequently excludes difficult-to-evaluate patients. Moreover, results from relatively small proof-of-principle studies have not been extended with randomized, controlled trials. As a result, currently, there is no clear evidence to support the value of any particular treatment approach over others. To avoid further unnecessary patient suffering and to identify optimal therapy as rapidly as possible, large randomized, controlled trials encompassing multicenter, international collaborations will be necessary.

New therapeutic approaches for adult T-cell leukaemia

Adult T-cell leukaemia or lymphoma is an aggressive malignant disease of mature activated T cells caused by human T-cell lymphotropic virus type I. Patients with this disease have a very poor outlook because of intrinsic chemoresistance and severe immunosuppression. In acute adult T-cell leukaemia, clinical trials in Japan show that although non-targeted combinations of chemotherapy improve response, they do not have a significant effect on complete remission and survival. Antiretroviral therapy with combination zidovudine and interferon alfa, which induces a high rate of complete remission and lengthens survival, should be the first treatment option in acute adult T-cell leukaemia. Patients with adult T-cell lymphoma might benefit from initial aggressive chemotherapy followed by antiretroviral therapy. To prevent relapse in all patients allogeneic bone-marrow transplantation when feasible, or additional targeted therapy, should be mandatory. Based on current pathophysiology, we discuss promising new drugs such as arsenic trioxide, proteasome inhibitors, retinoids, and angiogenesis inhibitors, as well as cellular immunotherapy.

Treatment of T-cell non-hodgkin’ lymphoma

T-cell non-Hodgkin's lymphoma (NHL) represents approximately 10% to 15% of all lymphomas in Western countries. Patients with T-cell NHL are often treated similarly to patients with intermediate grade B-cell NHL, although many reports have demonstrated lower overall survival rates in patients with T-cell NHL compared to patients with B-cell NHL. Updated classifications have recognized specific clinical and pathologic T-cell entities, such as peripheral T-cell lymphoma, not otherwise characterized, angioimmunoblastic lymphoma, systemic anaplastic T-cell lymphoma, adult T-cell leukemia/lymphoma, subcutaneous panniculitis-like T-cell lymphoma, hepatosplenic T-cell lymphoma, extranodal natural killer (NK)/T-cell lymphoma nasal type, and enteropathy-type intestinal T-cell lymphoma. Furthermore, these distinct T-cell NHL subtypes often warrant individualized diagnostic and therapeutic strategies, such as the associated cytophagic histiocytic panniculitis and hemophagocytic syndrome with subcutaneous panniculitis-like T-cell lymphoma, the chromosomal translocation t(2;5), leading to the nucleophosmin anaplastic lymphoma kinase fusion protein, viral pathogenesis of Epstein-Barr virus, human T-cell lymphotropic virus type-1 associated with extranodal NK/T-cell lymphoma nasal type and adult T-cell leukemia/lymphoma, respectively, and the role of radiation therapy in extranodal NK/T-cell lymphoma nasal type. Other active therapeutic agents in T-cell NHL include purine and pyrimidine antimetabolite agents (eg, nucleoside analogues and gemcitabine, respectively), denileukin diftitox, and antinucleoside or retinoic acid with interferon-alpha combination treatment. The exact role of transplantation in patients with T-cell NHL is unknown, but several case series have documented the feasibility of autologous and allogeneic transplant with reported long-term survival rates similar to transplanted B-cell NHL. Identification of relevant proto-oncogenes and tumor suppressor genes involved in the pathogenesis of T-cell NHL, such as the nucleophosmin anaplastic lymphoma kinase fusion protein, p53 and retinoblastoma gene, cyclin-dependent kinase inhibitors, histone deacetylation inhibitors, and infectious etiologies (eg, Epstein-Barr virus and Helicobacter pylori), in addition to their interplay with the various regulatory pathways of cell-cycle progression and apoptosis, represent potential candidates for molecular-based therapy. Prospective multi-institution clinical trials are critically important to determine the most effective treatment regimens that will continue to improve cure rates in these aggressive, yet treatable and often curable, diseases.