Radiotherapy is essential after complete response to asparaginase-containing chemotherapy in early-stage extranodal nasal-type NK/T-cell lymphoma: A multicenter study from the China Lymphoma Collaborative Group (CLCG)

Can the radiation dose be safely reduced in the treatment of nk/T cell lymphoma?

The aim of this study is to investigate the feasibility and safety of dose reduction in the radiotherapy of NK/T-cell lymphoma. A retrospective collection of clinical and treatment data was conducted on 41 patients. The analysis aimed to assess whether the reduction in radiation therapy dosage affected patients' local control and survival. Among the 41 patients, all achieved complete remission after the initial treatment. With a median follow-up of 28.4 months, all except one patient demonstrated good control within the irradiated area. In the entire cohort, a total of 6 patients died and none of the deaths were caused by local tumor failure. The 3-year overall survival rate and progression-free survival rate was 83.8%, 94.4%, respectively. The incidence of long-term toxicity was low. It seems safe to reduce the prophylactic radiation dose to 45 Gy and the preliminary treatment results are satisfactory, with further reduction in side effects.

Extranodal nasal-type NK/T lymphoma treated with chemotherapy and radiotherapy: case series from a European tertiary referral center and review of the literature

PURPOSE

Extranodal nasal-type NK/T-cell lymphoma (ENKTL) is very rare in western countries and few data are available regarding the prognosis and the outcome of patients treated for this disease. We aimed to evaluate the prognosis, the pattern and risk factors of disease failure after combined therapy and also performed a review of the literature.

PATIENTS AND METHODS

We retrospectively analyzed 20 patients with (ENKTL) who underwent L‑Asparaginase based chemotherapy followed by (chemo-) radiotherapy between 2010 and 2020 in our center. Data on clinical characteristics and irradiation were collected. Failure patterns were recorded as local (tumor site), regional (regional lymph nodes) or distant failure (metastasis and/or nonregional lymph nodes).

RESULTS

During a median follow-up period of 46 months, disease failure was observed in 8 patients (40%). The 3‑year progression-free survival (PFS) and overall survival (OS) rates were 62.5 and 83.0%, respectively. The failure patterns were local (n = 6, 30%), regional (n = 3, 15%) and distant (n = 4, 20%). Among patients with local failure, all failures occurred within the radiation fields (100%). Univariate analysis showed that bilateral regional lymph node involvement (p = 0.0002), initial circulating EBV viral load ≥ 3.5 log (p = 0.03) and no negativation of EBV PCR after induction CT (p = 0.0497) were independent predictors of PFS.

CONCLUSION

Patients with bilateral lymph node involvement and/or high EBV viral load have a significant recurrence rate despite multimodal therapy. These results need to be confirmed by larger studies. Given the high rate of local recurrence within radiotherapy fields, the value of dose escalation should be considered. Patients at risk of relapse should be included in dedicated trials.

Analysis of the treatment and prognosis of 266 cases of extranodal natural killer/T-cell lymphoma, nasal type in a single medical center

Objective

To assess the impact of different treatment strategies and risk factors on the prognosis of patients with extranodal NK/T-cell lymphoma, nasal type (ENKTL) in a single medical center.

Methods and analysis

The clinical features of 266 patients with ENKTL were retrospectively analyzed, among whom those in stages I and II received sandwich therapy, while those in stages III and IV underwent chemotherapy plus autologous hematopoietic stem cell transplantation. The Kaplan-Meier curves, univariate and multivariate Cox regression analyses were employed for survival and prognosis analysis. Statistical significance was set at P<0.05.

Results

Following treatment, the post-intervention outcomes demonstrated a complete remission (CR) rate of 71.05% and a partial remission (PR) rate of 3.76%. The 5-year progression-free survival (PFS) and overall survival (OS) rates were 70.4% and 70.9%, respectively. In addition, the PFS for patients in stage I/II was 79.8%, with an OS of 81.1%, whereas for those in stage III/IV, the PFS was 41.7% and the OS was 40.9%. Notably, the achievement of CR immediately after treatment was an independent prognostic factor (P<0.001). Patients in stage I/II depicted a favorable 5-year OS rate, while those in stage III/IV manifested a less favorable prognosis.

Conclusion

Stages of the disease and whether CR was achieved following treatment are important factors determining the survival and prognosis of patients with ENKTL. Further researches focusing on disease onset and mechanisms of drug resistance will contribute to better management of ENKTL.

Assessment of Bone Marrow Involvement in Extranodal NK/T-Cell Lymphoma: Positron Emission Tomography versus Bone Marrow Biopsy, and the Significance of Minimal Involvement by EBV+ Cells (KROG 18-09)

PURPOSE

This study aims to investigate the diagnostic significance of positron emission tomography/computed tomography (PET/CT) in assessing bone marrow (BM) involvement through a comparison of PET/CT findings with BM biopsy in extranodal natural killer/T-cell lymphoma.

MATERIALS AND METHODS

The medical records of 193 patients were retrospectively reviewed. Patients were categorized as having early-stage (PET-ES) or advanced-stage (PET-AS) disease based on PET/CT results. The BM involvement was classified into three groups according to BM biopsy: gross BM involvement, minimal BM involvement (defined as the presence of a limited number of Epstein-Barr virus-positive cells in BM), and no involvement. Calculations of the accuracy of PET/CT in detecting BM involvement and analysis of the clinical outcomes (progression-free survival [PFS] and overall survival [OS]) according to the BM biopsy status were performed.

RESULTS

PET/CT exhibited a sensitivity of 64.7% and a specificity of 96.0% in detecting gross BM involvement. For detecting any (both gross and minimal) BM involvement, the sensitivity was 30.4%, while the specificity was 99.0%. Only one patient (0.7%) demonstrated gross BM involvement among the PET-ES group. Survival outcomes of the PET-ES group with minimal BM involvement (3-year PFS, 55.6%; OS, 77.0%) were closer to those of the PET-ES group with no BM involvement (3-year PFS, 62.2%; OS, 80.6%) than to those of the PET-AS group (3-year PFS, 20.1%; OS, 29.9%).

CONCLUSION

PET/CT exhibits high specificity, but moderate and low sensitivity in detecting gross and minimal BM involvement, respectively. The clinical significance of minimal BM involvement for patients in the PET-ES group may be limited.

Phase 2 Clinical Trial of Simultaneous Boost Intensity Modulated Radiation Therapy With 3 Dose Gradients in Patients With Stage I-II Nasal Type Natural Killer/T-Cell Lymphoma: Long-Term Outcomes of Survival and Quality of Life

PURPOSE

The aim of this study was to investigate the treatment results and long-term quality of life in patients with early-stage extranodal natural killer/T-cell lymphoma who were prospectively treated with simultaneous boost intensity modulated radiation therapy (SIB-IMRT) with 3 dose gradients.

METHODS AND MATERIALS

Sixty patients with stage I-II nasal cavity natural killer/T-cell lymphoma (NKTCL) and Waldeyer's ring NKTCL were enrolled in a single-arm, prospective, phase 2 clinical trial from August 2011 to April 2015. All patients were treated with definitive radiation therapy combined with short-course induction chemotherapy. A newly designed SIB-IMRT scheme was uniformly adopted, with 54.6 Gy for the gross tumor volume (GTV) of the primary tumor and GTV of the positive lymph nodes, 50.7 Gy for the high-risk clinical target volume (CTV), and 45.5 Gy for the low-risk CTV, all delivered in 26 daily fractions. Before SIB-IMRT, L-asparaginase-based induction chemotherapy was used in 95.0% (57/60) of patients.

RESULTS

With a median follow-up time of 95.8 months, the 5-year locoregional recurrence-free survival, progression-free survival, and overall survival rates were 83.3%, 81.7%, and 88.3%, respectively. Dosimetric analysis in the first 21 patients showed satisfying conformality for planning target volume of GTV, high-risk CTV, and low-risk CTV, while the organs at risk were well protected. The results of long-term quality-of-life investigations in patients without progression were favorable, and nasal discomfort was the most common symptom. No grade 3 or 4 acute or late toxicities were observed.

CONCLUSIONS

The scheme of target volume delineation and dose setting that we designed has favorable clinical effects with mild side effects in treating patients with stage I-II nasal cavity NKTCL and Waldeyer's ring NKTCL.

Tislelizumab and radiation therapy in low-risk early-stage extranodal natural killer/T-cell lymphoma, nasal type: a phase II study protocol

Low-risk early-stage extranodal natural killer/T-cell lymphoma, nasal type has a favorable outcome with radiation therapy alone, and the addition of chemotherapy shows no survival benefit. Nonetheless, a proportion of patients will relapse or progress, with a dismal outcome, highlighting the need for a novel therapeutic strategy. Promising preliminary findings indicate the efficacy of PD-1/PD-L1 inhibitors in extranodal natural killer/T-cell lymphoma, nasal type, with good toxicity profiles. Here we describe the design of a phase II study (CLCG-NKT-2101), which is evaluating the safety and efficacy of adding anti-PD-1 antibody to the current radiation therapy regimen in low-risk early-stage extranodal natural killer/T-cell lymphoma, nasal type patients. Tislelizumab will be added in an inductive and concurrent way to radiation therapy. The primary end point will be the complete response rate after induction immunotherapy. Clinical trial registration: ClinicalTrials.gov (NCT05149170).

Comparative analysis of upper aerodigestive tract and non-upper aerodigestive tract in NK/T-cell lymphoma

OBJECTIVE

Nasal or extranasal natural killer/T-cell lymphoma (NKTCL) is a very rare aggressive lymphoma, but it is increasingly diagnosed. To evaluate some specificity by comparative analysis between primary upper aerodigestive tract (UAT) and non-upper aerodigestive tract (NUAT)NKTCL.

METHODS

A retrospective analysis was performed on NKTCL patients from January 2013 to November 2022 in our cancer center.

RESULTS

The majority of the lesions were UAT-NKTCL 70 cases (92.1%), the primary NUAT occurred in 6 cases. Patients in the UAT group were mainly in the early stage and in the low and medium risk, while those in the NUAT group were late stage and in high risk (p = 0.000). The expressions of CD3 and TIA-1 in UAT group were higher than those in NUAT group (p = 0.031, p = 0.003), while CD7 was dominant in NUAT group (p = 0.009). For early stage NKTCL, multivariate analysis suggested that gender and PINK score were independent factors affecting PFS and OS (p < 0.05). The 3 year OS rate in initial CR group was 90.1% versus 46.4% in non-CR group (p = 0.000). In advanced stage, KI67% and bone marrow involvement were independent factors affecting OS (p = 0.022, p = 0.038).

CONCLUSION

It was difficult to distinguish between UAT and NUAT-NKTCL from histopathology. NUAT-NKTCL patients did have advanced stage and poor outcome. The prognostic value of PINK score and bone marrow involvement was proposed. We aimed to improve initial CR rates, as well as to find new predictive models to predict the whole population.

Few and far between: clinical management of rare extranodal subtypes of mature T-cell and NK-cell lymphomas

While all peripheral T-cell lymphomas are uncommon, certain subtypes are truly rare, with less than a few hundred cases per year in the USA. There are often no dedicated clinical trials in these rare subtypes, and data are generally limited to case reports and retrospective case series. Therefore, clinical management is often based on this limited literature and extrapolation of data from the more common, nodal T-cell lymphomas in conjunction with personal experience. Nevertheless, thanks to tremendous pre-clinical efforts to understand these rare diseases, an increasing appreciation of the biological changes that underlie these entities is forming. In this review, we attempt to summarize the relevant literature regarding the initial management of certain rare subtypes, specifically subcutaneous panniculitis-like T-cell lymphoma, hepatosplenic T-cell lymphoma, intestinal T-cell lymphomas, and extranodal NK/T-cell lymphoma. While unequivocally established approaches in these diseases do not exist, we make cautious efforts to provide our approaches to clinical management when possible.

Intensive therapy can improve long-term survival in newly diagnosed, advanced-stage extranodal NK/T-cell lymphoma: A multi-institutional, real-world study

The study investigated the treatment and prognosis of advanced-stage extranodal natural killer/T-cell lymphoma (ENKTL). With a median follow-up of 75.03 months, the median overall survival (mOS) for the 195 newly diagnosed stage III/IV ENKTL patients was 19.43 months, and estimated 1-, 2-, 3- and 5-year OS were 59.5%, 46.3%, 41.8% and 35.1%, respectively. Chemotherapy (CT) + radiotherapy (RT) compared to CT alone (P = .007), and hematopoietic stem cell transplantation (HSCT) compared to non-HSCT (P < .001), both improved OS. For patients ≤60 years and ineligible for HSCT, other therapies with complete remission led to comparable OS (P = .141). Nine patients ever treated with chidamide achieved a median progression-free survival (mPFS) and mOS of 53.63 (range, 3.47-92.33) and 54.80 (range, 5.50-95.70) months, and four with chidamide maintenance therapy (MT) achieved a mPFS and mOS of 55.83 (range, 53.27-92.33) and 60.65 (range, 53.70-95.70) months, possibly providing an alternative option for non-HSCT patients. Non-anthracycline (ANT)- compared to ANT-, asparaginase (Aspa)- compared to non-Aspa- and gemcitabine (Gem)- compared to non-Gem-based regimens, prolonged PFS (P = .031; P = .005; P = .009) and OS (P = .010; P = .086; P = .003), respectively. Multivariate analysis demonstrated that Gem-based regimens improved PFS (HR = 0.691, P = .061) and OS (HR = 0.624, P = .037). Gem + Aspa combinations slightly improved PFS and OS compared to regimens containing Gem or Aspa alone (P > 0.05). First-line "intensive therapy," including CT (particularly Gem + Aspa regimens), RT, HSCT and alternative chidamide MT, was proposed and could improve long-term survival for advanced-stage ENKTLs. Ongoing prospective clinical studies may shed further light on the value of chidamide MT.

Extranodal lymphoma: pathogenesis, diagnosis and treatment

Approximately 30% of lymphomas occur outside the lymph nodes, spleen, or bone marrow, and the incidence of extranodal lymphoma has been rising in the past decade. While traditional chemotherapy and radiation therapy can improve survival outcomes for certain patients, the prognosis for extranodal lymphoma patients remains unsatisfactory. Extranodal lymphomas in different anatomical sites often have distinct cellular origins, pathogenic mechanisms, and clinical manifestations, significantly influencing their diagnosis and treatment. Therefore, it is necessary to provide a comprehensive summary of the pathogenesis, diagnosis, and treatment progress of extranodal lymphoma overall and specifically for different anatomical sites. This review summarizes the current progress in the common key signaling pathways in the development of extranodal lymphomas and intervention therapy. Furthermore, it provides insights into the pathogenesis, diagnosis, and treatment strategies of common extranodal lymphomas, including gastric mucosa-associated lymphoid tissue (MALT) lymphoma, mycosis fungoides (MF), natural killer/T-cell lymphoma (nasal type, NKTCL-NT), and primary central nervous system lymphoma (PCNSL). Additionally, as PCNSL is one of the extranodal lymphomas with the worst prognosis, this review specifically summarizes prognostic indicators and discusses the challenges and opportunities related to its clinical applications. The aim of this review is to assist clinical physicians and researchers in understanding the current status of extranodal lymphomas, enabling them to make informed clinical decisions that contribute to improving patient prognosis.

Characteristics and prognosis of distant metastasis after primary treatment for early-stage extranodal nasal-type natural killer/T-cell lymphoma from the China Lymphoma Collaborative Group database

This study aimed to investigate the characteristics and prognosis of distant metastasis (DM) after primary treatment for early-stage extranodal nasal-type natural killer (NK)/T-cell lymphoma (ENKTCL). A total of 1619 patients from the China Lymphoma Collaborative Group database were retrospectively reviewed. The cumulative incidence of DM was assessed using Fine and Gray's competing risk analysis. The correlation between DM sites was evaluated using phi coefficients, while DM sites were classified using hierarchical clustering. Regression analysis was used to assess the linear correlation between DM-free survival (DMFS) and overall survival (OS). The 5-year cumulative DM rate was 26.2%, with the highest annual hazard rate being in the first year (14.9%). The most frequent DM sites were the skin and soft tissues (SSTs, 32.4%) and distant lymph nodes (LNs, 31.3%). DM sites were categorized into four subgroups of distinct prognosis - distant LN, SST, extracutaneous site, and lymphoma-associated hemophagocytic lymphohistiocytosis. SST or distant LN, solitary metastasis, and late-onset DM demonstrated a relatively favorable prognosis. Contemporary chemotherapy significantly decreased DM rates and improved DMFS. Decreased DM rates were further associated with increased OS probabilities. Our findings improve the understanding of the variable clinical behaviors of early-stage ENKTCL based on four distinct DM sites and thus provide guidance for future therapeutic decisions, metastatic surveillance, and translational trial design.

Risk stratification and prognostic value of multi-modal MRI-based radiomics for extranodal nasal-type NK/T-cell lymphoma

BACKGROUND

Magnetic resonance imaging (MRI) performs well in the locoregional assessment of extranodal nasal-type NK/T-cell lymphoma (ENKTCL). It's important to assess the value of multi-modal MRI-based radiomics for estimating overall survival (OS) in patients with ENKTCL.

METHODS

Patients with ENKTCL in a prospectively cohort were systemically reviewed and all the pretreatment MRI were acquisitioned. An unsupervised spectral clustering method was used to identify risk groups of patients and radiomic features. A nomogram-revised risk index (NRI) plus MRI radiomics signature (NRI-M) was developed, and compared with the NRI.

RESULTS

The 2 distinct type I and II groups of the MRI radiomics signatures were identified. The 5-year OS rates between the type I and type II groups were 87.2% versus 67.3% (P = 0.002) in all patients, and 88.8% versus 69.2% (P = 0.003) in early-stage patients. The discrimination and calibration of the NRI-M for OS prediction demonstrated a better performance than that of either MRI radiomics or NRI, with a mean area under curve (AUC) of 0.748 and 0.717 for predicting the 5-year OS in all-stages and early-stage patients.

CONCLUSIONS

The NRI-M model has good performance for predicting the prognosis of ENKTCL and may help design clinical trials and improve clinical decision making.

Treatment of extranodal NK/T-cell lymphoma: From past to future

Extranodal NK/T-cell lymphoma (ENKTCL) is the most common subtype of T/NK-cell lymphoma in Asia and Latin America, but very rare in North American and Europe. Patient survival has improved significantly over the past two decades. However, standard treatment has not yet been established, although dozens of prospective trials have been conducted. To help understand how the treatment of ENKTCL has evolved in the past and what trends lie ahead, we have comprehensively reviewed the treatment of this aggressive malignancy, with a particular focus on neglected or unanswered issues, such as the optimal staging method, the best partner of asparaginase (Asp), the individualized administration of Asp, the preferred sequence of CT and RT and so on. Overall, the 5-year overall survival (OS) of patients with Ann Arbor stage I/II disease increased from < 50% in the early 20th century to > 80% in recent years, and the median OS of patients with Ann Arbor stage III/IV disease increased from < 1 year to more than 3 years. The improvement in patient survival is largely attributable to advances in radiation technology and the introduction of Asp and anti-PD-1/PD-L1 immunotherapy into practice. Radiotherapy is essential for patients with early-stage disease, while Asp-based chemotherapy (CT) and PD-1/PD-L1 inhibitors significantly improved the prognosis of patients with advanced-stage disease. ENKTCL management is trending toward simpler regimens, less toxicity, and higher efficacy. Novel drugs, such as manufactured T cells, monoclonal antibodies, and small molecule inhibitors, are being intensively investigated. Based on the fact that ENKTCL is highly resistant to cytotoxic drugs except Asp, and aggressive CT leads to higher toxicity rather than better outcomes, we recommend it is unnecessary to expend additional resources to compare different combinations of Asp with cytotoxic agents. Instead, more efforts should be made to optimize the use of Asp and immunotherapy to maximize efficacy and minimize toxicity, explore ways to overcome resistance to Asp and immunotherapy, identify novel treatment targets, and define subpopulations who may benefit more from specific treatments.

How we treat NK/T-cell lymphomas

Natural killer (NK)/T-cell lymphomas are aggressive malignancies with a predilection for Asian and South American populations. Epstein-Barr virus (EBV) infection in lymphoma cells is universal. Predominantly extranodal, NK/T-cell lymphomas are divided clinically into nasal (involving the nose and upper aerodigestive tract), non-nasal (involving the skin, gastrointestinal tract, testes, and other organs), and aggressive leukaemia/lymphoma (involving the marrow and multiple organs) subtypes. Initial assessment should include imaging with positron emission tomography computed tomography (PET/CT), quantification of plasma EBV DNA as a surrogate marker of lymphoma load, and bone marrow examination with in situ hybridization for EBV-encoded small RNA. Prognostication can be based on presentation parameters (age, stage, lymph node involvement, clinical subtypes, and EBV DNA), which represent patient factors and lymphoma load; and dynamic parameters during treatment (serial plasma EBV DNA and interim/end-of-treatment PET/CT), which reflect response to therapy. Therapeutic goals are to achieve undetectable plasma EBV DNA and normal PET/CT (Deauville score ≤ 3). NK/T-cell lymphomas express the multidrug resistance phenotype, rendering anthracycline-containing regimens ineffective. Stage I/II nasal cases are treated with non-anthracycline asparaginase-based regimens plus sequential/concurrent radiotherapy. Stage III/IV nasal, and non-nasal and aggressive leukaemia/lymphoma cases are treated with asparaginase-containing regimens and consolidated by allogeneic haematopoietic stem cell transplantation (HSCT) in suitable patients. Autologous HSCT does not improve outcome. In relapsed/refractory cases, novel approaches comprise immune checkpoint blockade of PD1/PD-L1, EBV-specific cytotoxic T-cells, monoclonal antibodies, and histone deacetylase inhibitors. Future strategies may include inhibition of signalling pathways and driver mutations, and immunotherapy targeting the lymphoma and its microenvironment.

Recent Advances in the Diagnosis and Treatment of Natural Killer Cell Malignancies

Simple Summary

Natural killer (NK)/T-cell lymphomas are aggressive extranodal Epstein–Barr virus (EBV)-positive malignancies. They can be divided into three subtypes: nasal (involving the nose and upper aerodigestive tract), non-nasal (involving skin, gastrointestinal tract, testis and other organs) and disseminated (involving multiple organs). Lymphoma cells are positive for CD3ε, CD56, cytotoxic molecules and EBV-encoded small RNA. There is a predilection for Asian and Central/South American populations. Genome-wide association studies have identified lymphoma susceptibility loci in Asians. Positron emission tomography computed tomography and plasma EBV DNA quantification are crucial at diagnosis and follow-up. Stage I/II patients receive non-athracycline asparaginse-containing regimens, together with sequential/concurrent radiotherapy. Anthracycline-containing regimens are ineffective. Stage III/IV patients receive asparaginase-containing regimens, followed by allogeneic haematopoietic stem cell transplantation (HSCT). Autologous HSCT does not improve outcome. In relapsed/refractory patients, novel approaches include PD1/PD-L1 targeting, EBV-specific cytotoxic T-cells, and monoclonal antibodies. Small molecules including histone deacetylase inhibitors may be beneficial.

Abstract

Natural killer (NK)/T-cell lymphomas are aggressive malignancies. Epstein–Barr virus (EBV) infection in lymphoma cells is invariable. NK/T-cell lymphomas are divided into nasal, non-nasal, and disseminated subtypes. Nasal NK/T-cell lymphomas involve the nasal cavity and the upper aerodigestive tract. Non-nasal NK/T-cell lymphomas involve the skin, gastrointestinal tract, testis and other extranodal sites. Disseminated NK/T-cell lymphoma involves multiple organs, rarely presenting with a leukaemic phase. Lymphoma cells are positive for CD3ε (not surface CD3), CD56, cytotoxic molecules and EBV-encoded small RNA. There is a predilection for Asian and Central/South American populations. Genome-wide association studies have identified lymphoma susceptibility loci in Asian patients. Positron emission tomography computed tomography and plasma EBV DNA quantification are crucial evaluations at diagnosis and follow-up. Stage I/II patients typically receive non-athracycline regimens containing asparaginse, together with sequential/concurrent radiotherapy. Anthracycline-containing regimens are ineffective. Stage III/IV patients are treated with asparaginase-containing regimens, followed by allogeneic haematopoietic stem cell transplantation (HSCT) in suitable cases. Autologous HSCT does not improve outcome. In relapsed/refractory patients, novel approaches are needed, involving PD1/PD-L1 targeting, EBV-specific cytotoxic T-cells, and monoclonal antibodies. Small molecules including histone deacetylase inhibitors may be beneficial in selected patients. Future strategies may include targeting of signalling pathways and driver mutations.

The optimal timing of radiotherapy in the combination treatment of limited-stage extranodal natural killer/T-cell lymphoma, nasal type: an updated meta-analysis

This study was designed to explore the relative efficacy and toxicity of upfront radiotherapy (RT) and late RT in combination treatments for patients with limited-stage extranodal natural killer/T-cell lymphoma nasal type (LS-ENKTL). We searched for clinical trials in the PubMed database that compared upfront RT with late RT in the combined treatment of patients with LS-ENKTL. We systematically evaluated the differences in survival, treatment response, and treatment-related adverse events (AEs) between these two groups. Ten retrospective studies with a total of 1752 patients were included. Upfront RT significantly prolonged the overall survival (OS) and progression-free survival (PFS) of patients compared to late RT in combination with chemotherapy (CT) (HR = 0.72, 95% CI 0.59-0.88, P = 0.001 for OS; HR = 0.57, 95% CI 0.41-0.79, P = 0.0007 for PFS). The complete remission (CR) rate in the upfront RT group was superior to that in the late RT group (HR = 1.61, 95% CI 1.09-2.37, P = 0.02). Patients experienced similar local recurrence-free survival (LRFS), objective response rates (ORR), and toxicity between these two arms (P > 0.05 for all) in the analysis of each subgroup. The survival benefit of upfront RT was not correlated with the RT dose, concurrent chemoradiotherapy (CCRT) (or not), or the CT regimen (P > 0.05 for all). Without compromises in terms of toxicity, RT dose, and treatment modality, upfront RT can significantly benefit OS, PFS, and CR compared to late RT in combination treatment. These findings verified that the upfront RT regimen is more suitable for patients with LS-ENKTL.

Modern Radiation Therapy for Extranodal Nasal-Type NK/T-cell Lymphoma: Risk-Adapted Therapy, Target Volume, and Dose Guidelines from the International Lymphoma Radiation Oncology Group

In the multidisciplinary management of early-stage extranodal natural killer/T-cell lymphoma, nasal type (ENKTCL), with curative intent, radiation therapy is the most efficacious modality and is an essential component of a combined-modality regimen. In the past decade, utilization of upfront radiation therapy and non-anthracycline-based chemotherapy has improved treatment and prognosis. This guideline mainly addresses the heterogeneity of clinical features, principles of risk-adapted therapy, and the role and appropriate design of radiation therapy. Radiation therapy methods (including target volume definition, dose and delivery methods) are crucial for optimizing cure for patients with early-stage ENKTCL. The application of the principles of involved site radiation therapy in this lymphoma entity often leads to a more extended clinical target volume (CTV) than in other lymphoma types because it usually presents with primary tumor invasion, multifocal lesions, or extensive submucosal infiltration beyond the macroscopic disease. The CTV varies across different primary sites and is classified mainly into nasal, nonnasal upper aerodigestive tract (UADT), and extra-UADT entities. This review is a consensus of the International Lymphoma Radiation Oncology Group regarding the approach to radiation therapy, target-volume definition, optimal dose, and dose constraints in ENKTCL treatment.

The promising outcome with simultaneous integrated boost intensity modulated radiotherapy in confined nasal extranodal NK/T-cell lymphoma

The study aimed to retrospectively analyze the prognosis of patients with stage IE nasal extranodal natural killer/T-cell lymphoma (ENKTL) with dose reduction to clinical target volume (CTV) by using simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT). Forty-four patients were reviewed retrospectively. The prescribed dose was 45 Gy/25 fractions for extended involved-field site and 50-55 Gy/25 fractions for primary tumor site by using SIB-IMRT. The 5-year overall survival (OS), local control (LC) and progression-free survival (PFS) were 81.2%, 93.0%, and 78.8%, respectively. The complete response (CR) rate was 85.4% (37/44). Three patients (6.8%) patients had local failure and 3 (6.8%) patients developed systemic failure. There was only one patient had grade 3 mucositis and 2 patients had grade 3 or grade 4 hematologic toxicities. For patients with stage IE nasal ENKTL, appropriate dose reduction to CTV by SIB-IMRT strategy is feasible and safe with a promising outcome.

Association of improved overall survival with decreased distant metastasis following asparaginase-based chemotherapy and radiotherapy for intermediate- and high-risk early-stage extranodal nasal-type NK/T-cell lymphoma: a CLCG study

BACKGROUND

This study evaluated the survival benefit of asparaginase (ASP)-based versus non-ASP-based chemotherapy combined with radiotherapy in a real-world cohort of patients with early-stage extranodal nasal-type natural killer/T-cell lymphoma (ENKTCL).

PATIENTS AND METHODS

We identified 376 patients who received combined radiotherapy with either ASP-based (ASP, platinum, and gemcitabine; n = 286) or non-ASP-based (platinum and gemcitabine; n = 90) regimens. The patients were stratified into low-, intermediate-, and high-risk groups using the early stage-adjusted nomogram-revised risk index. Overall survival (OS) and distant metastasis (DM)-free survival (DMFS) between the chemotherapy regimens were compared using inverse probability of treatment weighting (IPTW) and multivariable analyses.

RESULTS

ASP-based (versus non-ASP-based) regimens significantly improved 5-year OS (84.5% versus 73.2%, P = 0.021) and DMFS (84.4% versus 74.5%, P = 0.014) for intermediate- and high-risk patients, but not for low-risk patients in the setting of radiotherapy. Moreover, ASP-based regimens decreased DM, with a 5-year cumulative DM rate of 14.9% for ASP-based regimens compared with 25.1% (P = 0.014) for non-ASP-based regimens. The survival benefit of ASP-based chemotherapy and radiotherapy remained consistent after adjusting the confounding variables using IPTW and multivariate analyses; additional sensitivity analyses confirmed these results.

CONCLUSIONS

The findings provided support for ASP-based chemotherapy and radiotherapy as a first-line treatment strategy for intermediate- and high-risk early-stage ENKTCL.

First-line non-anthracycline-based chemotherapy for extranodal nasal-type NK/T-cell lymphoma: a retrospective analysis from the CLCG

The present study investigated the survival benefit of non-anthracycline (ANT)-based vs ANT-based regimens in a large-scale, real-world cohort of patients with extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKTCL). Within the China Lymphoma Collaborative Group (CLCG) database (2000-2015), we identified 2560 newly diagnosed patients who received chemotherapy with or without radiotherapy. Propensity score matching (PSM) and multivariable analyses were used to compare overall survival (OS) and progression-free survival (PFS) between the 2 chemotherapy regimens. We explored the survival benefit of non-ANT-based regimens in patients with different treatments in early-stage disease and in risk-stratified subgroups. Non-ANT-based regimens significantly improved survivals compared with ANT-based regimens. The 5-year OS and PFS were 68.9% and 59.5% for non-ANT-based regimens compared with 57.5% and 44.5% for ANT-based regimens in the entire cohort. The clinical advantage of non-ANT-based regimens was substantial across the subgroups examined, regardless of stage and risk-stratified subgroup, and remained significant in early-stage patients who received radiotherapy. The survival benefits of non-ANT-based regimens were consistent after adjustment using multivariable and PSM analyses. These findings provide additional evidence supporting non-ANT-based regimens as a first-line treatment of patients with ENKTCL.

Durable Response to Sintilimab and Chidamide in a Patient With Pegaspargase- and Immunotherapy-Resistant NK/T-Cell Lymphoma: Case Report and Literature Review

The prognosis of patients with relapsed/refractory NK/T-cell lymphoma (NKTCL) is dismal. Immunotherapy has showed encouraging anti-tumor activity in patients with asparaginase-resistant NKTCL; however, only a portion of patients benefit and the median response duration is rather short. Treatment strategies have not been identified for immunotherapy-resistant NKTCL. We describe a patient with primary cutaneous NKTCL experienced disease progression after pegaspargase-based chemotherapy and PD-1 inhibitor (sintilimab)-based immunotherapy. Following a combined treatment of sintilimab and the HDAC inhibitor chidamide, the patient achieved a durable complete molecular response with mild toxicity. This case indicates that the combination of PD-1 inhibitor and HDAC inhibitor might be a treatment choice for immunotherapy-resistant NKTCL.

Progression-free survival at 24 months and subsequent survival of patients with extranodal NK/T-cell lymphoma: a China Lymphoma Collaborative Group (CLCG) study

Limited evidence supports the use of early endpoints to evaluate the success of initial treatment of extranodal NK/T-cell lymphoma (ENKTCL) in the modern era. We aim to analyze progression-free survival at 24 months (PFS24) and subsequent overall survival (OS) in a large-scale multicenter cohort of patients. 1790 patients were included from the China Lymphoma Collaborative Group (CLCG) database. Subsequent OS was defined from the time of PFS24 or progression within 24 months to death. OS was compared with age- and sex-matched general Chinese population using expected survival and standardized mortality ratio (SMR). Patients who did not achieve PFS24 had a median OS of 5.3 months after progression, with 5-year OS rate of 19.2% and the SMR of 71.4 (95% CI, 62.9-81.1). In contrast, 74% patients achieved PFS24, and the SMR after achieving PFS24 was 1.77 (95% CI, 1.34-2.34). The observed OS rate after PFS24 versus expected OS rate at 5 years was 92.2% versus 94.3%. Similarly, superior outcomes following PFS24 were observed in early-stage patients (5-year OS rate, 92.9%). Patients achieving PFS24 had excellent outcome, whereas patients exhibiting earlier progression had a poor survival. These marked differences suggest that PFS24 may be used for study design and risk stratification in ENKTCL.

Risk-based, response-adapted therapy for early-stage extranodal nasal-type NK/T-cell lymphoma in the modern chemotherapy era: A China Lymphoma Collaborative Group study

We aimed to determine the survival benefits of chemotherapy (CT) added to radiotherapy (RT) in different risk groups of patients with early-stage extranodal nasal-type NK/T-cell lymphoma (ENKTCL), and to investigate the risk of postponing RT based on induction CT responses. A total of 1360 patients who received RT with or without new-regimen CT from 20 institutions were retrospectively reviewed. The patients had received RT alone, RT followed by CT (RT + CT), or CT followed by RT (CT + RT). The patients were stratified into different risk groups using the nomogram-revised risk index (NRI). A comparative study was performed using propensity score-matched (PSM) analysis. Adding new-regimen CT to RT (vs RT alone) significantly improved overall survival (OS, 73.2% vs 60.9%, P < .001) and progression-free survival (PFS, 63.5% vs 54.2%, P < .001) for intermediate-risk/high-risk patients, but not for low-risk patients. For intermediate-risk/high-risk patients, RT + CT and CT + RT resulted in non-significantly different OS (77.7% vs 72.4%; P = .290) and PFS (67.1% vs 63.1%; P = .592). For patients with complete response (CR) after induction CT, initiation of RT within or beyond three cycles of CT resulted in similar OS (78.2% vs 81.7%, P = .915) and PFS (68.2% vs 69.9%, P = .519). For patients without CR, early RT resulted in better PFS (63.4% vs 47.6%, P = .019) than late RT. Risk-based, response-adapted therapy involving early RT combined with CT is a viable, effective strategy for intermediate-risk/high-risk early-stage patients with ENKTCL in the modern treatment era.

Extranodal NK/T cell lymphoma

Extranodal natural killer (NK)/T cell lymphoma (ENKTL) is a distinct subtype of Non-Hodgkin’s lymphoma mainly involving the nasal area. Since the entity was first recognized, treatment strategies have been evolving from anthracycline-based chemotherapy and radiotherapy to L-asparaginase containing regimens and recently immune checkpoint inhibitors. With the currently used combined chemotherapy and radiotherapy, more than 70% of patients with localized disease can be cured. L-asparaginase containing regimens have significantly improved treatment outcomes among patients with advanced disease. However, the treatment outcomes of patients with disease refractory to L-asparaginase containing regimens or who experience recurrence remain poor. In this article, we cover the current treatments for ENKTL and emerging treatment approaches.

Validation of nomogram-revised risk index and comparison with other models for extranodal nasal-type NK/T-cell lymphoma in the modern chemotherapy era: indication for prognostication and clinical decision-making

Derived from our original nomogram study by using the risk variables from multivariable analyses in the derivation cohort of 1383 patients with extranodal NK/T-cell lymphoma, nasal-type (ENKTCL) who were mostly treated with anthracycline-based chemotherapy, we propose an easily used nomogram-revised risk index (NRI), validated it and compared with Ann Arbor staging, the International Prognostic Index (IPI), Korean Prognostic Index (KPI), and prognostic index of natural killer lymphoma (PINK) for overall survival (OS) prediction by examining calibration, discrimination, and decision curve analysis in a validation cohort of 1582 patients primarily treated with non-anthracycline-based chemotherapy. The calibration of the NRI showed satisfactory for predicting 3- and 5-year OS in the validation cohort. The Harrell’s C-index and integrated Brier score (IBS) of the NRI for OS prediction demonstrated a better performance than that of the Ann Arbor staging system, IPI, KPI, and PINK. Decision curve analysis of the NRI also showed a superior outcome. The NRI is a promising tool for stratifying patients with ENKTCL into risk groups for designing clinical trials and for selecting appropriate individualized treatment.

Effect of age as a continuous variable on survival outcomes and treatment selection in patients with extranodal nasal-type NK/T-cell lymphoma from the China Lymphoma Collaborative Group (CLCG)

PURPOSE

The aim of this study was to determine the impact of analyzing age as a continuous variable on survival outcomes and treatment selection for extranodal nasal-type NK/T-cell lymphoma.

RESULTS

The risk of mortality increased with increasing age, without an apparent cutoff point. Patients' age, as a continuous variable, was independently associated with overall survival after adjustment for covariates. Older early-stage patients were more likely to receive radiotherapy only whereas young-adult advanced-stage patients tended to receive non-anthracycline-based chemotherapy. A decreased risk of mortality with radiotherapy versus chemotherapy only in early-stage patients (HR, 0.347, P < 0.001) or non-anthracycline-based versus anthracycline-based chemotherapy in early-stage (HR, 0.690, P = 0.001) and advanced-stage patients (HR, 0.678, P = 0.045) was maintained in patients of all ages.

CONCLUSIONS

These findings support making treatment decisions based on disease-related risk factors rather than dichotomized chronological age.

PATIENTS AND METHODS

Data on 2640 patients with extranodal nasal-type NK/T-cell lymphoma from the China Lymphoma Collaborative Group database were analyzed retrospectively. Age as a continuous variable was entered into the Cox regression model using penalized spline analysis to determine the association of age with overall survival (OS) and treatment benefits.

NK/T-cell lymphomas

NK/T-cell lymphomas are extranodal EBV-related malignancies, mostly of NK-cell and occasionally of T-cell lineage. They are divided into nasal, non-nasal, and disseminated subtypes. Nasal NK/T-cell lymphomas involve the nose, nasopharynx and the upper aerodigestive tract. Non-nasal NK/T-cell lymphomas involve the skin, gastrointestinal tract, testis and other sites. Disseminated NK/T-cell lymphoma involves multiple organs, and may present with a leukemic phase. Initial evaluation requires positron emission tomography computed tomography (PET/CT) and quantification of circulating EBV DNA. Radiotherapy alone is inadequate with frequent relapses. Anthracycline-containing regimens are ineffective. Regimens incorporating asparaginase are currently the standard. For stage I/II disease, combined chemotherapy and radiotherapy is recommended. For stage III/IV disease, asparaginase-containing regimens are needed. Autologous hematopoietic stem cell transplantation (HSCT) is of limited efficacy, whereas allogeneic HSCT may be useful in patients with stage III/IV and relapsed diseases. Immunotherapy with antibodies against CD30, programmed cell death protein 1 and CD38 is promising.

Epstein-Barr Virus-Positive Natural Killer/T-Cell Lymphoma

Extranodal natural killer/T-cell lymphoma, nasal type (ENKL), is a rare malignancy of Non-Hodgkin lymphoma characterized by an aggressive clinical course and poor prognosis. It shows strong association with Epstein-Barr virus infection and occurs more commonly in Asia and Latin America. Various genetic alterations have been identified in ENKL by gene expression profiling and sequencing techniques. The frequent deletion of chromosome 6q21 was reported to lead to the silence of several tumor suppressor genes. Also, there have been novel genetic mutations that were recently uncovered and were found to frequently activate several oncogenic pathways, including the JAK/STAT, NF-κB, and MAPK pathways. Besides, we believe that deregulated single genes and epigenetic dysregulation might be relevant to the mechanism of this disease and thus, may have the potential to shed lights on the development of new therapeutic strategies. The consensus on the standard treatment for ENKL has not yet been currently established. For localized ENKL patients, radiotherapy with concurrent chemotherapy and sequential patterns of chemotherapy and radiotherapy are recommended as first-line therapy. As for advanced or relapsed/refractory ENKL patients, the application of non-anthracycline-containing regimens have significantly improved the clinical outcome, contributing to higher response rate, longer overall survival and progression-free survival. Hematopoietic stem cell transplantation is widely recommended for consolidation after a complete remission or partial remission has been achieved. The anti-programmed death 1 antibody, an immune checkpoint inhibitor, has demonstrated favorable results in treating relapsed or refractory ENKL. Of the current ENKL treatment, researchers are still striving to validate how radiotherapy and chemotherapy should be optimally combined and which of the non-anthracycline-containing regimens is superior. In this review, we summarize the main genetic alterations frequently found in ENKL and their role in providing new insights into the therapeutic targets of this disease, and highlight the recent findings regarding new biologic markers, novel therapeutic strategies applied to this intriguing neoplasm.

Risk-Dependent Conditional Survival and Failure Hazard After Radiotherapy for Early-Stage Extranodal Natural Killer/T-Cell Lymphoma

IMPORTANCE

Prognosis of early-stage extranodal natural killer/T-cell lymphoma (NKTCL) is usually estimated and stratified at diagnosis, but how the prognosis actually evolves over time for patients who survived after curative treatment is unknown.

OBJECTIVE

To assess conditional survival and failure hazard over time based on risk categories, previous survival, and treatment.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study reviewed the clinical data of 2015 patients with early-stage NKTCL treated with radiotherapy identified from the China Lymphoma Collaborative Group multicenter database between January 1, 2000, and December 31, 2015. Patients were stratified into low-, intermediate- and high-risk groups according to a previously established prognostic model. Median follow-up was 61 months for surviving patients. Data analysis was performed from December 1, 2017, to January 30, 2018.

EXPOSURES

All patients received radiotherapy with or without chemotherapy.

MAIN OUTCOMES AND MEASURES

Conditional survival defined as the survival probability, given patients have survived for a defined time, and annual hazard rates defined as yearly event rate.

RESULTS

A total of 2015 patients were included in the study (mean [SD] age, 43.3 [14.6] years; 1414 [70.2%] male); 1628 patients (80.8%) received radiotherapy with chemotherapy, and 387 (19.2%) received radiotherapy without chemotherapy. The 5-year survival rates increased from 69.1% (95% CI, 66.6%-71.4%) at treatment to 85.3% (95% CI, 81.7%-88.2%) at year 3 for conditional overall survival and from 60.9% (95% CI, 58.3%-63.3%) at treatment to 84.4% (95% CI, 80.6%-87.6%) at year 3 for conditional failure-free survival. The annual hazards decreased from 13.7% (95% CI, 13.0%-14.3%) for death and 22.1% (95% CI, 21.0%-23.1%) for failure at treatment to less than 5% after 3 years (death: range, 0%-3.9% [95% CI, 3.7%-4.2%]; failure: 1.2% [95% CI, 1.0%-1.4%] to 4.2% [95% CI 3.9%-4.6%]). Intermediate-risk (11.4% [95% CI, 10.5%-12.3%]) and high-risk (21.6% [95% CI, 20.0%-23.2%]) patients had initially higher but significantly decreased death hazards after 3 years (<6%, range: 0%-5.9% [95% CI, 5.2%-6.7%]), whereas low-risk patients maintained a constantly lower death hazard of less than 5% (range, 0%-4.8%; 95% CI, 4.4%-5.3%). In high-risk patients, radiotherapy combined with non-anthracycline-based regimens were associated with higher conditional overall survival before year 3 compared with anthracycline-based regimens (hazard ratio [HR] for death, 1.49; 95% CI, 1.13-1.95; P = .004 at treatment; HR, 1.60; 95% CI, 1.07-2.39; P = .02 at 1 year; and HR, 1.77; 95% CI, 0.94-3.33; P = .07 at 2 years) or radiotherapy alone (HR, 2.42; 95% CI, 1.73-3.39; P < .001 at treatment; HR, 1.82; 95% CI, 1.05-3.17; P = .03 at 1 year; and HR, 2.69; 95% CI, 1.23-5.90; P = .01 at 2 years).

CONCLUSIONS AND RELEVANCE

The survival probability increased and the hazards of failure decreased in a risk-dependent manner among patients with early NKTCL after radiotherapy. These dynamic data appear to provide accurate information on disease processes and continual survival expectations and may help researchers design additional prospective clinical trials and formulate risk-adapted therapies and surveillance strategies.

Castleman disease versus lymphoma in neck lymph nodes: a comparative study using contrast-enhanced CT

BACKGROUND

The purpose of this study was to determine the contrast-enhanced CT characteristics for differentiating between Castleman disease (CD) and lymphoma in neck lymph nodes.

METHODS

This retrospective study evaluated the number (solitary or multiple), strength of contrast-enhancement, type of contrast-enhancement, surrounding vessels, contrast-enhanced Hounsfield unit (HU) values, and anatomical distributions of lymph nodes in 34 patients with confirmed CD and 55 patients with newly diagnosed untreated lymphoma. Independent t-tests, receiver operating characteristic (ROC) curve analysis, and chi-square tests were used to evaluate the variables and CT features.

RESULTS

Several significant differences were found between CD and lymphoma. The interval between first contrast-enhanced CT and biopsy/surgery was significantly longer in the CD group (mean 72 ± 105 days, median 60 days) than in the lymphoma patients (mean 30 ± 2 days, median 12 days; p = 0.015). The lymphoma patients presented significantly more often with fatigue and fever (p = 0.023 and p = 0.016 respectively) than did the CD subjects. HU values of nodules after enhancement were significantly higher in the CD patients than in the lymphoma patients. In cases involving multiple lymph nodes, in all the CD cases, all affected nodes were located in only the left or right side of the neck, not bilaterally. ROC analysis showed a significant difference in contrast-enhanced CT attenuation values between lymphoma and CD (p < 0.001, area under the curve = 0.954), with a cut-off value of 92.5 HU. We constructed a decision tree according to these imaging characteristics.

CONCLUSIONS

Contrast-enhanced CT can be useful for differentiating between CD and lymphoma.