Mild Toxicity and Favorable Prognosis of High–Dose and Extended Involved-Field Intensity-Modulated Radiotherapy for Patients With Early-Stage Nasal NK/T-Cell Lymphoma

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.

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.

Extranodal Natural Killer/T-Cell Lymphomas: Current Approaches and Future Directions

Extranodal natural killer/T(NK/T)-cell lymphoma (ENKTL) is a rare subtype of non-Hodgkin lymphoma that typically presents with an isolated nasal mass, but a sizeable minority present with advanced stage disease and have a significantly poorer prognosis. Those with limited disease are standardly treated with chemotherapy and radiation while those with advanced stage disease are treated with L-asparaginase containing chemotherapy regimens. The addition of modern radiation therapy techniques and the incorporation of L-asparaginase into chemotherapy regimens have significantly improved outcomes in this disease, but relapses and death from relapsed disease remain frequent. Given the high rate of relapse, several novel therapies have been evaluated for the treatment of this disease. In this review, we explore the current standard of care for ENKTL as well as novel therapies that have been evaluated for its treatment and the biologic understanding behind these therapies.

First-line chemoradiation with or without chidamide (tucidinostat) in patients with early stage intermediate- and high-risk early-stage extranodal nasal-type natural killer/T-cell lymphoma: a randomized phase 2 study in China

PURPOSE

We investigated the safety and efficacy profile of intensity-modulated radiation therapy (IMRT) followed by gemcitabine, dexamethasone, cisplatin (GDP), plus chidamide in the first-line setting for intermediate- and high-risk early-stage extranodal natural killer/T-cell lymphoma, nasal type (ENKTCL).

METHODS

This was an open-label, randomized phase 2 trial performed at two centers in China. Patients were eligible if they were newly-diagnosed with intermediate- and high-risk early-stage ENKTCL with at least one risk factor based on a nomogram-revised risk index:> 60 years old, elevated serum lactate dehydrogenase, invasion of the primary tumor, stage II or Eastern Cooperative Oncology Group performance status > 1 or stage II disease. Patients were treated with IMRT followed by GDP, with or without chidamide, in the first-line setting. Two-year progression-free survival (PFS) comprised the primary endpoint. Toxicities, the 2-year overall survival (OS), and the response rate comprised the secondary endpoints.

RESULTS

Eligible patients (n = 74) were enrolled between May 2015 and December 2019. Among them, 37 patients were treated with IMRT+GDP+chidamide (chidamide group), while 37 cases were treated with IMRT+GDP (control group). Follow-up comprised a median of 43.4 months (range, 1.0-74.6 months). The objective response rate was 86.5% in the chidamide group and 78.4% in the control group (P = 0.359) at the end of treatment completion. The 2-year OS and PFS rates were 89.2% and 75.2% in the chidamide group versus 83.8% (P = 0.388) and 70.2% (P = 0.821) in the control group. The main adverse events were hematological toxicities and mucositis, with similar rates in the two groups (P > 0.05).

CONCLUSIONS

The addition of chidamide to IMRT + GDP as first-line treatment achieved similar treatment outcomes and tolerable toxicities in patients with intermediate- and high-risk ENKTCL.

GELAD chemotherapy with sandwiched radiotherapy for patients with newly diagnosed stage IE/IIE natural killer/T-cell lymphoma: a prospective multicentre study

Early-stage natural killer/T-cell lymphoma (NK/TCL) patients usually receive a combination of chemotherapy and radiotherapy, but the optimal treatment approach has not yet been established. This study aimed to investigate the efficacy and safety profile of a novel chemotherapy regimen and sandwiched radiotherapy in early-stage NK/TCL. Patients with newly diagnosed stage IE/IIE disease were eligible. Patients were initially treated with two courses of the GELAD regimen (gemcitabine 1·0 g/m² day 1, etoposide 60 mg/m² days 1-3, pegaspargase 2000 units/m² day 4, and dexamethasone 40 mg days 1-4), followed by intensity-modulated radiotherapy (IMRT; 50-56 Gy in 25-28 fractions) and two additional courses of GELAD chemotherapy. A total of 52 patients were enrolled. The overall response rate and complete response rate per Lugano 2014 criteria were 94·2% and 92·3% respectively. With a median follow-up of 32 months, the estimated four-year overall survival rate and progression-free survival rate were 94·2% [95% confidence interval (CI), 83·2% to 93·1%] and 90·4% (95% CI, 78·4% to 95·9%) respectively. The most common adverse events were related to pegaspargase. Haematological toxicities were mild, with grade 3/4 neutropenia in 15·4% of patients. Our study provides a new approach with high activity and improved safety for the treatment of early-stage NK/TCL patients. This study was registered at www.clinicaltrials.gov as NCT02733458.

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.

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

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

Risk-adapted survival benefit of IMRT in early-stage NKTCL: a multicenter study from the China Lymphoma Collaborative Group

This study evaluated the survival benefit of intensity-modulated radiation therapy (IMRT) compared with 3-dimension conformal radiation therapy (3D-CRT) in a large national cohort of patients with early-stage extranodal nasal-type natural killer/T-cell lymphoma (NKTCL). This retrospective study reviewed patients with early-stage NKTCL treated with high-dose radiation therapy (RT; ≥45 Gy) at 16 Chinese institutions. Patients were stratified into 1 of 4 risk groups based on the number of risk factors: low risk (no factors), intermediate-low risk (1 factor), intermediate-high risk (2 factors), and high-risk (3-5 factors). Of the 1691 patients, 981 (58%) received IMRT, and 710 (42%) received 3D-CRT. Unadjusted 5-year overall survival (OS) and progression-free survival (PFS) were 75.9% and 67.6%, respectively, for IMRT compared with 68.9% (P = .004) and 58.2% (P < .001), respectively, for 3D-CRT. After propensity score match and multivariable analyses to account for confounding factors, IMRT remained significantly associated with improved OS and PFS. The OS and PFS benefits of IMRT persisted in patients treated with modern chemotherapy regimens. Compared with 3D-CRT, IMRT significantly improved OS and PFS for high-risk and intermediate-high-risk patients but provided limited benefits for low-risk or intermediate-low-risk patients. A risk-adapted survival benefit profile of IMRT can be used to select patients and make treatment decisions.

Upfront radiation is essential for high-risk early-stage extranodal NK/T-cell lymphoma, nasal type: comparison of two sequential treatment modalities combining radiotherapy and GDP (gemcitabine, dexamethasone, and cisplatin) in the modern era

Early/upfront radiation was associated with improved survivals compared with late radiation for early-stage NK/T-cell lymphoma (NKTCL) in the old era when anthracycline-base chemotherapy (CT) prevailed. However, in the modern era of effective l-asparaginase/gemcitabine-based CT, the optimal timing of radiation is unclear. In this study, 75 patients with newly diagnosed NKTCL, who were treated with combined involved-field intensity-modulated radiotherapy and GDP (gemcitabine, dexamethasone, and cisplatin) were retrospectively reviewed, including 45 from the RT + CT group and 30 from the CT + RT ± CT group. Compared with CT + RT ± CT, RT + CT sequence achieved superior progression-free survival (5-year PFS: 81.6% vs. 56.0%, p = .017) and locoregional control (LRC) (90.8% vs. 66.9%; p = .020). Responses, overall survivals or adverse event incidences did not differ across the groups. Upfront RT was a powerful prognostic variable for favorable PFS (HR 0.302; 95% CI: 0.125-0.729; p = .008). It indicated that upfront RT administration remains vital in enhancing LRC and survival for localized NKTCL in the modern era.

Characteristics, Prognostic Factors, and Survival of Patients with NK/T-Cell Lymphoma of Non-upper Aerodigestive Tract: A 17-Year Single-Center Experience

Purpose

The extranodal natural killer (NK)/T-cell lymphoma (NKTCL) of non-upper aerodigestive tract (NUAT) was found to have clinical heterogeneity compared with NKTCL of the upper aerodigestive tract (UAT) in small scale studies. We conducted this study in a much larger cohort to analyze the clinical characteristics, prognostic factors, treatment modality, and clinical outcomes of patients with NUAT-NKTCL.

Materials and Methods

From January 2001 to December 2017, a total of 757 NKTCL patients were identified and included in this study, including 92 NUAT-NKTCL patients (12.2%) and 665 UAT-NKTCLpatients (87.8%).

Results

NUAT-NKTCL patients had relatively poorer performance status, more unfavorable prognostic factors, and more advanced stage, compared with UAT-NKTCL patients. The 5-year overall survival (OS) was 34.7% for NUAT-NKTCL, which was significantly worse than UAT-NKTCL (64.2%, p<0.001). The median OS duration was 30.9 months for NUAT-NKTCL. Multivariate analysis showed that presence with B symptoms and elevated serum lactate dehydrogenase independently predicted worse OS. International prognostic index score and prognostic index of natural killer lymphoma score still had prognostic values in NUAT-NKTCL, while the Ann Arbor system could not accurately predict the OS.

Conclusion

NUAT-NKTCL is a distinctive subtype of NKTCL in many aspects. Patients with NUAT-NKTCL have relatively poorer performance status, more unfavorable prognostic factors, more advanced stage, and poorer prognosis.

Promising clinical outcomes of sequential and "Sandwich" chemotherapy and extended involved-field intensity-modulated radiotherapy in patients with stage IE /IIE extranodal natural killer/T-cell lymphoma

BACKGROUND

The optimal treatment for the rare subtype of non-Hodgkin lymphoma, extranodal natural killer/T-cell lymphoma (ENKTL), nasal-type, has not been clearly defined. The purpose of the study was to investigate the efficacy of sequential and "Sandwich" chemotherapy and extended involved-field intensity-modulated radiotherapy (IMRT) in patients with stage I_E /II_E extranodal ENKTL, nasal-type.

METHODS

One hundred and fifty-five patients with stage I_E /II_E nasal-type ENKTL were enrolled in the study, including 99 patients treated with sequential chemotherapy and extended involved-field IMRT (SCRT) and 56 patients with "Sandwich" chemotherapy and extended involved-field IMRT and chemotherapy (SCRCT). All patients were treated with extended involved-field IMRT with median dose of 54.6 Gy to the primary tumor and positive lymph nodes. Ninety-four patients had Ann Arbor stage I_E disease, and 61 patients had stage II_E disease.

RESULTS

The 5-year rates of loco-regional recurrence (LRR), progression-free survival (PFS), and overall survival (OS) were 17.0%, 78.5%, and 84.7%, respectively. Univariate analysis revealed that EBV DNA copy after treatment (normal vs elevated level) was significant prognostic factor for LRR, PFS, and OS (P < 0.001); therapeutic method (SCRT vs SCRCT) was significant prognostic factor for PFS (71.0% vs 91.8%, P = 0.011), but there was no significant effect on 5-year LRR and OS (22.2% vs 8.2%, P = 0.051 for LRR; 80.9% vs 91.8%, P = 0.199 for OS).

CONCLUSIONS

Compared with SCRT, SCRCT was significantly associated with higher PFS rates and showed a trend toward improved loco-regional control. EBV DNA copy after treatment is a good index for recurrence and prognosis for stage I_E /II_E ENKTL patients.

Risk-dependent curability of radiotherapy for elderly patients with early-stage extranodal nasal-type NK/T-cell lymphoma: A multicenter study from the China Lymphoma Collaborative Group (CLCG)

BACKGROUND

The purpose of this study was to determine the curability of early-stage extranodal nasal-type NK/T-cell lymphoma (NKTCL) in response to radiotherapy and non-anthracycline-based chemotherapy in elderly patients.

METHODS

In this multicenter study from the China Lymphoma Collaborative Group (CLCG) database, 321 elderly patients with early-stage NKTCL were retrospectively reviewed. Patients received radiotherapy alone (n = 87), chemotherapy alone (n = 59), or combined modality therapy (CMT, n = 175). Patients were classified into low- or high-risk groups using four prognostic factors. Observed survival in the study cohort vs expected survival in age- and sex-matched individuals from the general Chinese population was plotted using a conditional approach and subsequently compared using a standardized mortality ratio (SMR).

RESULTS

Radiotherapy conveyed a favorable prognosis and significantly improved survival compared to chemotherapy alone. The 5-year overall survival (OS) and progression-free survival (PFS) were 61.2% and 56.4%, respectively, for radiotherapy compared with 44.7% and 38.3%, respectively, for chemotherapy alone (P < 0.001). The combination of a non-anthracycline-based chemotherapy regimen and radiotherapy significantly improved PFS compared to combination of an anthracycline-based chemotherapy regimen and radiotherapy (71.2% vs 44.2%, P = 0.017). Low-risk patients following radiotherapy (SMR, 0.703; P = 0.203) and high-risk patients who achieved PFS at 24 months (SMR, 1.490; P = 0.111) after radiotherapy showed survival equivalent to the general Chinese population.

CONCLUSIONS

Our findings indicate a favorable curability for this malignancy in response to radiotherapy and non-anthracycline-based chemotherapy, providing a risk-adapted follow-up and counsel scheme in elderly patients.

Salvage radiotherapy improves survival in patients with locoregionally relapsed stage IE-IIE extranodal natural killer/T-cell lymphoma, nasal type

Background

This study aims to retrospectively analyze the salvage treatment outcomes and prognostic factors of patients with early stage locoregionally recurrent (LRR) extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKTCL).

Methods

Between January 1995 and December 2014, 540 patients with stage IE-IIE ENKTCL received chemotherapy (ChT) and/or radiotherapy (RT) in our hospital, and among these, 56 patients who experienced LRR were included in this study. Salvage treatments included RT alone in 4 patients (7.1%), ChT alone in 30 patients (53.6%), and ChT combined with RT in 22 patients (39.3%). Median RT dose was 50 Gy (range 36-60 Gy). The effect of salvage treatment on overall survival (OS) rate from start of initial treatment (IT) as well as that after recurrence was analyzed.

Results

The overall median follow-up time from IT was 35.9 months, with a 3-year OS of 72.7%. The median follow-up time after relapse was 14.8 months, and the 3-year OS after relapse was 57.8%. Compared to ChT alone (n=30), treatment with salvage RT (n=26) improved the OS from IT (p=0.040) and after relapse (p=0.009); further, re-irradiation improved the OS from IT (p=0.018) and after relapse (p=0.019). Acute and late toxicities after re-irradiation were mostly grades 1-2 (84.3%). At both univariate and multivariate analyses, better Karnofsky Performance Score (KPS), RT in IT, and RT in salvage treatment were found to be significant factors influencing OS after recurrence.

Conclusion

Salvage RT improved survival in patients with LRR stage IE-IIE ENKTCL, and the treatment toxicity was acceptable.

A phase II prospective study of the "Sandwich" protocol, L-asparaginase, cisplatin, dexamethasone and etoposide chemotherapy combined with concurrent radiation and cisplatin, in newly diagnosed, I/II stage, nasal type, extranodal natural killer/T-cell lymphoma

Nasal-type, extranodal NK/T cell lymphoma (ENKTCL) is a special type of lymphomas with geographic and racial specificity. Up to now, the standard first-line treatment is still not unified. In our previous report, the "sandwich" protocol produced good results. Continuing to use the "sandwich" mode, a new chemotherapy composed of L-asparaginase, cisplatin, etoposide and dexamethasone (LVDP) plus concurrent chemoradiotherapy (CCRT) was conducted in more patients with newly diagnosed, I/II stage ENKTCL. The results showed that 66 patients were enrolled. Overall response rate was 86.4% including 83.3% complete response and 3.0% partial remission. With the median follow-up of 23.5 months, 3-year overall survival and 3-year progression-free survival were 70.1% and 67.4%, respectively. The survival rate in stage II and extra-cavity stage I was significantly less than that in limited stage I (p < 0.05). Therefore, we thought that the "sandwich" mode was worthy of being generalized and LVDP combined with CCRT was an effective protocol for I/II stage ENKTCL. But this regimen was not suitable for all stage I/II patients and warrants larger sample and layering investigation. This study was a registered clinical trial with number ChiCTR-TNC-12002353.

Advances in the treatment of extranodal NK/T-cell lymphoma, nasal type

Extranodal natural killer/T-cell lymphoma, nasal type (ENKL) is a subtype of mature T- and natural killer cell lymphomas characterized by its association with Epstein-Barr virus and extranodal involvement. Although there is geographic variance in the frequency of ENKL, its clinical features are similar between Western countries and endemic areas, such as East Asia. Anthracycline-containing chemotherapy is not recommended to treat ENKL. No standard treatment has been established based on the results of randomized controlled trials. In patients with localized disease, radiotherapy is a core component of the recommended first-line therapy. Radiotherapy administered at 50 to 54 Gy, extended involved-site radiotherapy considering tumor invasiveness, and the use of intensity modulated radiation therapy or volumetric modulated arc therapy are associated with efficacy of radiotherapy. Although the use of concurrent chemoradiotherapy has been supported by the results of clinical trials, accumulating evidence supports the use of sequential chemoradiotherapy with non-anthracycline-containing regimens that include l-asparaginase and/or platinum anticancer agents. l-asparaginase-containing chemotherapy is a key component of first-line treatments for systemic ENKL. Hematopoietic stem cell transplantation is recommended as a front-line consolidation therapy for newly diagnosed advanced-stage ENKL. Newer agents including immune checkpoint inhibitors are being investigated for treating ENKL. In this modern ENKL treatment era, multidisciplinary efforts are needed to identify the best timing and sequencing of radiotherapy, l-asparaginase, platinum, newer agents, and hematopoietic stem cell transplantation.

A comparison of treatment modalities for nasal extranodal natural killer/T-cell lymphoma in early stages: The efficacy of CHOP regimen based concurrent chemoradiotherapy

This study was designed to evaluate the efficacy of several treatment modalities, including CHOP based concurrent chemoradiotherapy (CCRT), for the patients with stage IE or IIE nasal extranodal NK/T-cell lymphoma (nasal ENKL). The cases were retrieved between 2000 and 2010 (n=94), and were followed to the end of February 2016. The patients were grouped into A (chemotherapy alone; CT alone), B (sequential treatment) and C (CCRT). For those with efficacy evaluation for overall treatment (n=90), CR was attained in 60.0% (18/30), 69.8% (30/43) and 76.5% (13/17) patients in the group A, B and C, respectively. The 5-year OS rate was 35.2%, 41.9% and 70.6% in the group A, B and C, respectively. For patients with early stage diseases (IE and IIE), the ECOG performance status and the Ann Arbor stage were significant prognostic factors for both OS and PFS. Among the stage IE patients, besides the ECOG performance status, three prognostic factors which related to treatments (treatment modalities, efficacy of initial and overall treatment) were significant against OS or PFS. In conclusion, compared to chemotherapy alone and sequential treatment, nasal ENKL patients in early stages, especially stage IE, benefit the most from CHOP based concurrent chemoradiotherapy.

Intensity-modulated radiotherapy has superior outcomes to three-dimensional conformal radiotherapy in patients with stage IE-IIE extranodal nasal-type natural killer/T-cell lymphoma

We compared the treatment outcomes, toxicities and prognoses of patients with stage IE-IIE extranodal natural killer/T-cell lymphoma (ENKTL) treated with intensity-modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3DCRT). Newly diagnosed early-stage ENKTL patients (N = 173) were enrolled and received extended involved-field radiotherapy following induction chemotherapy. Patients were treated with 3DCRT (n = 98) or IMRT (n = 75). One-to-one matching of the IMRT and 3DCRT groups was performed through propensity score matching, which yielded 23 pairs of patients. The two groups achieved similar complete remission rates before and after radiotherapy (P > 0.05). All patients were followed up for a median of 41 months. The rates of local recurrence-free survival (LRFS, P < 0.001), progression-free survival (PFS, P = 0.003) and overall survival (OS, P = 0.003) were longer in the IMRT than 3DCRT group. In the matched patients, IMRT was still associated with superior LRFS (P = 0.024), but not with improved PFS (P = 0.113) or OS (P = 0.115). Multivariate analysis also suggested IMRT was a favorable independent factor for LRFS (HR = 2.230, P = 0.043), but not for PFS (P = 0.195) or OS (P = 0.116). Equivalent acute toxicities were observed for 3DCRT and IMRT; however, among stage II patients who had received cervical irradiation, the rate of late xerostomia was lower in the IMRT than 3DCRT group (38.5% vs. 66.7%, P = 0.046). Overall, IMRT yielded a better treatment response and local control than 3DCRT, and tended to reduce late xerostomia in patients with cervical irradiation, but failed to enhance OS. Thus, IMRT is recommended for the treatment of stage IE-IIE ENKTL patients.

Current treatment approaches for NK/T-cell lymphoma

Extranodal NK/T-cell lymphoma, nasal type (ENKL), is a form of lymphoma characterized by preferential extranodal involvement, Epstein-Barr virus (EBV) association, and geographic diversity in incidence. ENKL tumor cells express P-glycoprotein, which is related to multidrug resistance (MDR). This MDR phenomenon is thought to be the major reason why ENKL is resistant to anthracycline-containing chemotherapies and has led researchers to explore novel therapeutic strategies. Since the early 2000s, next-generation therapies, including upfront radiotherapy, chemotherapy, or concurrent chemoradiotherapy using non-MDR-related drugs, have markedly changed the management of ENKL. However, a recent large retrospective study in Japan revealed several limitations of next-generation therapies, in particular that they resulted in almost no improvement of early disease progression. This review will summarize the current management of ENKL, primarily based on clinical trial results, and provide clues for better future management.

Radiotherapy improves survival in early stage extranodal natural killer/T cell lymphoma patients receiving asparaginase-based chemotherapy

This study retrospectively investigated asparaginase-based chemotherapy treatment outcomes with or without radiotherapy in 143 patients with stage IE-IIE extranodal natural killer/T cell lymphoma (ENKTCL). All patients received a median of three cycles of asparaginase-based chemotherapy, while 121 patients received radiotherapy following the chemotherapy. The complete remission (CR) rate for all patients post-chemotherapy was 58.7%, and rose to 73.4% by the end of treatment. Patients who received radiotherapy achieved better survival outcomes than those who did not (89.7% vs. 49.0% for 2-year overall survival (OS), P<0.001; 86.8% vs. 37.4% for 2-year progression-free survival (PFS), P<0.001). Additionally, even patients who achieved CR post-chemotherapy exhibited differential survival rates with or without radiotherapy (90.8% vs. 60% for 2-year OS, P=0.006; 86.1% vs. 60% for 2-year PFS, P=0.044). Multivariate analysis revealed that radiotherapy was an independent factor favoring OS (HR=0.098, 95%CI=0.031-0.314, P=0.001) and PFS (HR=0.156, 95%CI=0.062-0.396, P=0.001). Thus, radiotherapy is recommended for stage IE-IIE ENKTCL patients treated with asparaginase-based chemotherapy, even in cases of CR following chemotherapy.

Treatment outcomes of and prognostic factors for definitive radiotherapy with and without chemotherapy for Stage I/II nasal extranodal NK/T-cell lymphoma

Treatment strategies for nasal extranodal NK/T-cell lymphoma (ENKTL), including sequential chemotherapy followed by radiotherapy (SCRT), concurrent chemoradiotherapy (CCRT), or radiotherapy alone (RT), remain varied. The purpose of this study was to assess the treatment outcome, the toxicity, and the potential prognostic factors for patients with early-stage nasal ENKTL treated using definitive RT (minimum of 50 Gy) with or without chemotherapy. From 1998 to 2014, 37 patients were included in the study. Eight patients were treated with RT alone, 1 with CCRT, and 28 with SCRT. Local regional control (LRC), progression-free survival (PFS), and overall survival (OS) were calculated using the Kaplan-Meier method. RT resulted in an overall response rate of 91.2%, with a complete response rate of 78.4%. After a median follow-up time of 36.8 months, the 3-year LRC, PFS and OS were 87.4%, 64.0% and 76.3%, respectively. Acute severe toxicity (Grade 3) of mucositis was observed in 6 (16.2%) of the 37 patients. In univariate analyses, extensive disease (Stage I/II with local invasiveness) and the presence of B symptoms were significantly associated with a poor PFS, whereas extensive disease was significantly associated with a poor OS. Multivariate analysis identified the presence of extensive disease as an independent predictor of PFS (P < 0.001) and OS (P = 0.015). High-dose RT with or without chemotherapy reported promising locoregional control and a favorable outcome for patients with early-stage nasal ENKTL without local invasiveness. Further investigation of new treatment strategies for patients with local invasiveness is warranted.

Patterns of Primary Tumor Invasion and Regional Lymph Node Spread Based on Magnetic Resonance Imaging in Early-Stage Nasal NK/T-cell Lymphoma: Implications for Clinical Target Volume Definition and Prognostic Significance

PURPOSE

This study aimed to determine the pathways of primary tumor invasion (PTI) and regional lymph node (LN) spread based on magnetic resonance imaging (MRI) in early-stage nasal NK/T-cell lymphoma (NKTCL), to improve clinical target volume (CTV) delineation and evaluate the prognostic value of locoregional extension patterns.

METHODS AND MATERIALS

A total of 105 patients with newly diagnosed early-stage nasal NKTCL who underwent pretreatment MRI were retrospectively reviewed. All patients received radiation therapy with or without chemotherapy.

RESULTS

The incidences of PTI and regional LN involvement were 64.7% and 25.7%, respectively. Based on the incidence of PTI, involved sites surrounding the nasal cavity were classified into 3 risk subgroups: high-risk (>20%), intermediate-risk (5%-20%), and low-risk (<5%). The most frequently involved site was the nasopharynx (35.2%), followed by the maxillary (21.9%) and ethmoid (21.9%) sinuses. Local disease and regional LN spread followed an orderly pattern without LN skipping. The retropharyngeal nodes (RPNs) were most frequently involved (19.0%), followed by level II (11.4%). The 5-year overall survival (OS), progression-free survival (PFS), and locoregional control (LRC) rates for all patients were 72.8%, 65.2%, and 90.0%, respectively. The presence of PTI and regional LN involvement based on MRI significantly and negatively affected PFS and OS.

CONCLUSIONS

Early-stage nasal NKTCL presents with a high incidence of PTI but a relatively low incidence of regional LN spread. Locoregional spread followed an orderly pattern, and PTI and regional LN spread are powerful prognostic factors for poorer survival outcomes. CTV reduction may be feasible for selected patients.

The Roles of Radiotherapy and Chemotherapy in the Era of Multimodal Treatment for Early-Stage Nasal-Type Extranodal Natural Killer/T-Cell Lymphoma

PURPOSE

To evaluate radiotherapy (RT) and chemotherapy (CT) treatments of early-stage extranodal natural killer/T-cell lymphoma (ENKTL).

MATERIALS AND METHODS

Fifty-five patients with stage I or II ENKTL [n=39 (71%) and 16 (29%) patients, respectively] who were treated with RT between 1999 and 2013 were analyzed retrospectively. The median age was 54 years (range, 24-81). Patients were grouped by treatment modality as RT alone [n=19 (35%)], upfront CT plus RT [CT+RT, n=16 (29%)], and concurrent chemoradiotherapy [CCRT, n=20 (36%)]. The median RT dose was 48 Gy. Patient characteristics between each treatment group were well balanced. Patterns of failure and survival were analyzed.

RESULTS

The overall response rate after RT was 94.6%. Ten patients experienced distant failure, and seven experienced local failure comprising five in-field and two out-field failures. The local and distant failure rates in the RT-alone group were the same (16%). In the CT+RT group, the most common failure sites were local (19%). In the CCRT group, the most common failures were distant (25%). At a median follow-up of 56 months (range, 1-178 months), the 5-year overall survival (OS) and progression-free survival rates were 66% and 54%, respectively. The 5-year OS rate for the RT-alone and CT+RT groups were 76% and 69%, respectively, and the 2-year OS rate for the CCRT group was 62% (p=0.388).

CONCLUSION

In the era of multimodal treatment for ENKTL, RT alone using advanced techniques should be considered for local disease control, whereas maintenance CT regimens should be considered for distant disease control.

Chemoradiotherapy for localized extranodal natural killer/T-cell lymphoma, nasal type, using a shrinking-field radiation strategy: multi-institutional experience

PURPOSES

The prognosis of localized extranodal natural killer/T-cell lymphoma, nasal type (ENKTL), has improved with the development of chemoradiotherapy. However, conventional extended-field radiotherapy may cause optic disorders. Our group has employed smaller radiation fields in an attempt to avoid toxicity. The efficacy and toxicity of treatments were evaluated.

MATERIALS AND METHODS

Chemoradiotherapy was delivered with a shrinking-field radiotherapy strategy. The endpoints of this study were overall survival (OS), local control (LC), progression-free survival (PFS), and toxicity.

RESULTS

Fifteen patients with localized ENKTL were treated. After irradiation (median, 40 Gy) to the tumor plus a prophylactic volume, a reduced treatment volume to the tumor was boosted (median, 10 Gy). Twelve patients underwent chemoradiotherapy and 3 patients received radiotherapy alone. A complete response was achieved in 12 and a partial response in 3 patients. The 5-year OS, PFS, and LC rates were 80, 67, and 93 %, respectively. Distant recurrence occurred in 4 patients and locoregional and distant recurrence in 1 patient. Cataract (grade 3) and dry eye (grade 2) were observed as late adverse events in 1 patient each.

CONCLUSIONS

Sufficiently high OS and LC were achieved with acceptable toxicities. Appropriate target volumes may be smaller with newer chemotherapy regimens.

A single institution experience of extranodal natural killer/T cell lymphoma of nasal type

Extranodal natural killer/T cell lymphoma (ENKTL) nasal type is a rare form of non-Hodgkin lymphoma that is more commonly seen in Asia and Latin America than in North America or Europe. The purpose of this study was to determine the treatment outcomes with a combined modality approach and whether treatment outcomes varied according to ethnicity in patients with ENKTL, nasal type in Toronto, Canada. Patients presenting with ENKTL, nasal type, between 1994 and 2011 were retrospectively reviewed. Patient characteristics, including the patient's ethnic origin, treatment details and outcomes were recorded and analyzed for significant differences between Asian and Caucasian patients. A total of 34 patients were identified: 16 Asian, 16 Caucasian, one Aboriginal and one Hispanic. All patients had nasal cavity involvement. The majority had localized disease: stage I (n = 22), stage II (n = 6); and stage IV in six patients. Combined radiotherapy (RT) and chemotherapy was intended for 32 of the 34 patients, with two receiving RT alone. Median RT dose was 45 Gy (range: 35-50.4 Gy). Response to initial treatment was observed in 44% of patients. Two-year disease-free survival was 17.8% (Asian patients: 18.8%, Caucasians: 20%, p = 0.82), and overall survival 39.2% (Asian patients: 30%, Caucasians: 42%, p = 0.52). There were no significant differences in clinical outcomes in terms of patient ethnicity. A combined modality approach (with cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP] chemotherapy administered initially) is of limited effectiveness. We have now adopted the use of RT as the initial treatment approach, followed by multiagent chemotherapy.

Risk-adapted therapy for early-stage extranodal nasal-type NK/T-cell lymphoma: analysis from a multicenter study

Patients with early-stage extranodal nasal-type NKTCL were classified as low risk or high risk using 5 independent prognostic factors. Risk-adapted therapy of RT alone for the low-risk group and RT consolidated by CT for the high-risk group proved the most effective treatment.

Concurrent Chemoradiation Therapy Followed by Consolidation Chemotherapy for Localized Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type

PURPOSE

To evaluate the effectiveness of concurrent chemoradiation therapy (CCRT) with 40 Gy followed by consolidation chemotherapy for localized extranodal natural killer (NK)/T-cell lymphoma (ENKTL), nasal type.

METHODS AND MATERIALS

From August 2004 to August 2012, 62 patients with newly diagnosed stage IE to IIE ENKTL underwent CCRT followed by consolidation chemotherapy. The median RT dose was 40 Gy. Cisplatin, 30 mg/m(2), was administered weekly during the RT course. Responders to CCRT were encouraged to undergo consolidation chemotherapy. Three different consolidation chemotherapy regimens were used consecutively: VIPD (etoposide, ifosfamide, cisplatin, and dexamethasone); VIDL (etoposide, ifosfamide, and dexamethasone followed by intramuscular injection of l-asparaginase); and MIDLE (methotrexate, etoposide, ifosfamide, mesna, and l-asparaginase).

RESULTS

The median follow-up period was 49 months (range 8-112). After completion of CCRT, 56 patients (90.3%) had a complete response, 4 (6.4%) had a partial response, 1 (1.6%) had stable disease, and 1 patient (1.6%) had progressive disease (PD). Consolidation chemotherapy was recommended to 61 patients, after excluding the patient with PD, but was actually delivered to 58. Of these 58 patients, 56 (96.5%) had a complete response and 2 (3.5%) had PD. During the follow-up period, 17 patients (including 3 with PD) experienced progression. The median interval to progression was 11 months (range 1-61). Local failure developed in 6 patients, of whom, 2 had developed progression outside the RT field. For all patients, the 3-year overall survival, progression-free survival, and local control rates were 83.1%, 77.1%, and 92.4%, respectively. Grade ≥3 nonhematologic toxicity developed in only 3 patients (4.8%).

CONCLUSIONS

Excellent clinical outcomes were achieved using CCRT with 40 Gy followed by consolidation chemotherapy. Additional investigation, however, is warranted to confirm our findings.

Modern radiation therapy for extranodal lymphomas: field and dose guidelines from the International Lymphoma Radiation Oncology Group

Extranodal lymphomas (ENLs) comprise about a third of all non-Hodgkin lymphomas (NHL). Radiation therapy (RT) is frequently used as either primary therapy (particularly for indolent ENL), consolidation after systemic therapy, salvage treatment, or palliation. The wide range of presentations of ENL, involving any organ in the body and the spectrum of histological sub-types, poses a challenge both for routine clinical care and for the conduct of prospective and retrospective studies. This has led to uncertainty and lack of consistency in RT approaches between centers and clinicians. Thus far there is a lack of guidelines for the use of RT in the management of ENL. This report presents an effort by the International Lymphoma Radiation Oncology Group (ILROG) to harmonize and standardize the principles of treatment of ENL, and to address the technical challenges of simulation, volume definition and treatment planning for the most frequently involved organs. Specifically, detailed recommendations for RT volumes are provided. We have applied the same modern principles of involved site radiation therapy as previously developed and published as guidelines for Hodgkin lymphoma and nodal NHL. We have adopted RT volume definitions based on the International Commission on Radiation Units and Measurements (ICRU), as has been widely adopted by the field of radiation oncology for solid tumors. Organ-specific recommendations take into account histological subtype, anatomy, the treatment intent, and other treatment modalities that may be have been used before RT.

Concurrent IMRT and weekly cisplatin followed by GDP chemotherapy in newly diagnosed, stage IE to IIE, nasal, extranodal NK/T-Cell lymphoma

On the basis of the benefits of frontline radiation in early-stage, extranodal natural killer (NK)/T-cell lymphoma (ENKTL), we conducted the trial of concurrent chemoradiotherapy (CCRT) followed by three cycles of gemcitabine, dexamethasone and cisplatin (GDP). Thirty-two patients with newly diagnosed, stage IE to IIE, nasal ENKTL received CCRT (that is, all patients received intensity-modulated radiotherapy 56 Gy and cisplatin 30 mg/m² weekly, 3–5 weeks). Three cycles of GDP (gemcitabine 1000 mg/m² intravenously (i.v.) on days 1 and 8, dexamethasone 40 mg orally on days 1–4 and cisplatin 75 mg/m² i.v. on day 1 (GDP), every 21 days as an outpatient were scheduled after CCRT. All patients completed CCRT, which resulted in 100% response that included 24 complete responses (CRs) and eight partial responses. The CR rate after CCRT was 75.0% (that is, 24 of 32 responses). Twenty-eight of the 32 patients completed the planned three cycles of GDP, whereas four patients did not because they withdrew (n=1) or because they had an infection (n=3). The overall response rate and the CR rate were 90.6% (that is, 29 of 32 responses) and 84.4% (that is, 27 of 32 responses), respectively. Only two patient experienced grade 3 toxicity during CCRT (nausea), whereas 13 of the 30 patients experienced grade 4 neutropenia. The estimated 3-year overall survival and progression-free rates were 87.50% and 84.38%, respectively. In conclusion, CCRT followed by GDP chemotherapy can be a feasible and effective treatment strategy for stage IE to IIE nasal ENKTL.

Association between higher expression of YB-1 and poor prognosis in early-stage extranodal nasal-type natural killer/T-cell lymphoma

Aim: A recent study shows that YB-1-related biomarkers affect the prognosis of patients with natural killer/T-cell lymphoma (NKTCL). The aim of this study was to determine whether there is an association between YB-1 expression and the prognosis of patients with early-stage extranodal nasal-type NKTCL. Materials & methods: To clarify the roles of YB-1 in early-stage extranodal nasal-type NKTCL, we used immunohistochemical studies to examine YB-1 expression in 36 early-stage extranodal nasal-type NKTCL specimens. Results: Subsequently, YB-1 expression was correlated with clinicopathologic parameters. Higher expression of YB-1 was associated with an increased potential for relapse, poor disease-free survival and reduced overall survival. Discussion: Higher expression of YB-1 could be an independent risk factor for poor prognosis in patients with early-stage extranodal nasal-type NKTCL. Understanding the biology of YB-1-mediated pathways may lead to novel therapeutic strategies for early-stage extranodal nasal-type NKTCL.

Immunophenotypic and clinical differences between the nasal and extranasal subtypes of upper aerodigestive tract natural killer/T-cell lymphoma

PURPOSE

To investigate, in a large cohort of patients, the immunophenotypic and clinical differences of nasal and extranasal extranodal nasal-type natural killer/T-cell lymphoma of the upper aerodigestive tract (UADT-NKTCL) and examine the relevance of the immunophenotype on the clinical behavior, prognosis, and treatment.

METHODS AND MATERIALS

A total of 231 patients with UADT-NKTCL were recruited. One hundred eighty-one patients had primary location in the nasal cavity (nasal UADT-NKTCL), and 50 patients had primary extranasal UADT-NKTCL.

RESULTS

Patients with extranasal UADT-NKTCL had more adverse clinical features, including advanced-stage disease, regional lymph node involvement, B symptoms, and poor performance status, than patients with nasal UADT-NKTCL. In addition, CD56 and granzyme B were less frequently expressed in extranasal UADT-NKTCL. The 5-year overall survival rate was 74.1% for the entire group and 76.0% for early-stage disease. The 5-year overall survival rate for extranasal UADT-NKTCL was similar or superior to that of nasal UADT-NKTCL for all disease stages (76.9% vs 73.4%, P=.465), stage I disease (75.9% vs 79.2%, P=.786), and stage II disease (83.3% vs 50.3%, P=.018). CD56 expression and a Ki-67 proliferation rate ≥ 50% predicted poorer survival for extranasal UADT-NKTCL but not for nasal UADT-NKTCL.

CONCLUSIONS

Patients with nasal and extranasal UADT-NKTCL have significantly different clinical features, immunophenotypes, and prognosis. Extranasal UADT-NKTCL should be considered as a distinct subgroup apart from the most commonly diagnosed prototype of nasal UADT-NKTCL.

[Radiation therapy of sinonasal natural killer/T-cell lymphoma]

Natural killer (NK)/T-cell lymphoma are part of lymphoproliferative diseases, they are rare in Europe and the United States but relatively common in Asia and South America. Natural killer (NK)/T-cell lymphoma present clinically as destructive lesions of the upper aerodigestive tract with perforation of deep structures of the face, destruction of the palate or an invasion of orbits. Treatment modalities of these lymphomas are still discussed because of the lack of available studies and the rarity of this disease. Radiotherapy provides a rapid control of the disease and is positioned as a major treatment of localized stages of NK/T-cell lymphoma of the nasal cavity. We therefore studied the different forms of radiation therapy in the early stages of nasal NK/T-cell lymphoma.

Sequential chemotherapy followed by radiotherapy versus concurrent chemoradiotherapy in patients with stage I/II extranodal natural killer/T-cell lymphoma, nasal type

BACKGROUND

The purpose of this report is to summarize our clinical experience of patients with stage I/II extranodal natural killer (NK)/T-cell lymphoma, nasal type, treated using sequential chemotherapy followed by radiotherapy (SCRT) or concurrent chemoradiotherapy (CCRT).

METHODS

Forty-three patients with stage I/II extranodal NK/T-cell lymphoma, nasal type, who received SCRT (16 patients) or CCRT (27 patients) were included in the present analysis.

RESULTS

The median follow-up time was 39 months (range, 4-171 months) for all patients, 77 months (range, 4-171 months) for the SCRT group, and 31 months (range, 6-132 months) for the CCRT group. There were no statistically significant differences between the SCRT and CCRT groups with regard to the 3-year progression-free survival (PFS) (56% vs. 41%, P=0.823) and 3-year overall survival (OS) (75% vs. 59%, P=0.670). Univariate analysis revealed that patients with tumors confined to the nasal cavity and patients achieved complete remission had better PFS and OS rates, regardless of the treatment sequence. Multivariate analysis revealed that patients with tumors confined to the nasal cavity and patients aged ≤60 years had better OS rates.

CONCLUSION

The effect of SCRT and CCRT are similar in terms of survival outcomes of patients with stage I/II extranodal NK/T-cell lymphoma, nasal type. Our results show that tumors confined to the nasal cavity and an age ≤60 years were associated with a better prognosis.

Intensity-modulated radiotherapy versus three-dimensional conformal radiotherapy for stage I-II natural killer/T-cell lymphoma nasal type: dosimetric and clinical results

Background

This study was to compare radiotherapy treatment planning and treatment outcomes following three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) in stage I-II natural killer (NK)/T-cell lymphoma.

Methods

The cases of 94 patients with stage I-II NK/T-cell lymphoma, nasal type in the upper aerodigestive tract who treated between May 2005 and Dec 2008 were reviewed. These patients received radiotherapy with or without induction chemotherapy. Definitive radiotherapy was conducted using 3DCRT in 47 patients and IMRT in the other 47 patients with a regional field and a total dose of 50 Gy. Dosimetric pmeters of radiation treatment plans, local control probability (LCP), overall survival (OS), and toxicities were analyzed and compared between 3DCRT and IMRT.

Results

From the dosimetric analysis, IMRT demonstrated significantly better dose coverage and homogeneity than 3DCRT. However, after a median follow-up of 46 months, IMRT was not associated with improvements in 4y-OS (80.9% for 3DCRT vs. 82.7% for IMRT, p=0.87) or 4y-LCP (86.3% for 3DCRT vs. 88.9% for IMR p=0.85). Of the 18 patients who received cervical lymph node irradiation, those in the IMRT group received a lower mean parotid dose. Furthermore, at-risk organs were strictly kept within the safe dose range in both groups, and no severe late toxicity was observed.

Conclusions

IMRT provided better dose coverage than 3DCRT, although it failed to provide LCP and OS benefits. Definitive radiotherapy with a regional field and a total dose of 50 Gy is efficient and safe for NK/T-cell lymphoma using either IMRT or 3DCRT. However, IMRT may have the potential to reduce parotid gland hypofunction following cervical irradiation.

Novel therapies for peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are a diverse family of lymphoid neoplasms with poor prognosis. They represent approximately 6-10% of non-Hodgkin lymphomas with significant geographic variation. The median age at diagnosis varies with histology, however the majority of patients with PTCL are in their fifth or sixth decade of life. Until recently clinical development of new agents for PTCL was slow due to difficulties in making the correct diagnosis, lack of uniform classification and combination of rarity and biologic diversity of the group. In the last 5 years, significant advances were made to overcome these obstacles, leading to the approval of three new agents for relapsed and refractory PTCL by the Food and Drug Administration, based on well conducted prospective studies. Pralatrexate, a unique antifol, was the first agent granted approval, followed by romidepsin, a histone deacetylase inhibitor, and brentuximab vedotin, an immunoconjugate. Owing to the unique nature of these agents, durable responses were seen in patients with highly refractory disease, and some of these responses are long lasting after discontinuation of therapy. Accumulating data indicate that these novel agents have little cumulative toxicity and can be administered continuously to patients who are not candidates for consolidative stem-cell transplantation (SCT), with little impact on quality of life. They might also provide a new salvage option for patients eligible for SCT with no impact on autologous stem-cell collection or subsequent engraftment. New studies are underway to evaluate efficacy and safety of new agents in combination regimens for both newly diagnosed and relapsed/refractory PTCL. Several other investigational drugs showed promise in recent trials. This review focuses on novel therapies for T-cell lymphomas, their place in current treatment paradigms and future directions.

How I treat NK/T-cell lymphomas

Natural killer (NK)/T-cell lymphomas and NK-cell leukemias are aggressive malignancies. Occurring worldwide, they show a predilection for Asian and South American populations. Neoplastic cells are surface CD3-, cytoplasmic CD3ε+, CD56+, cytotoxic-molecule positive, Epstein-Barr virus (EBV) positive, with germline T-cell receptor gene. Lymphomas occur commonly in the nasal and upper aerodigestive region. Occasional cases present in the skin, salivary gland, testis, and gastrointestinal tract. Rare cases are disseminated with lymphadenopathy, hepatosplenomegaly, and a leukemic phase. Positron emission tomography computed tomography is useful in staging, as lymphomas are 18-fluorodeoxyglucose avid. Quantification of circulating EBV DNA is an accurate biomarker of tumor load. Nasal NK/T-cell lymphomas present mostly with stage I/II disease. Concomitant/sequential chemotherapy and radiotherapy is standard treatment. Radiotherapy alone is inadequate because of high systemic failure rate. For stage III/IV nasal, nonnasal, and disseminated lymphomas, systemic chemotherapy is indicated. Regimens containing l-asparaginase and drugs unaffected by P-glycoprotein are most effective. Hematopoietic stem cell transplantation (HSCT) is not indicated for early-stage nasal lymphomas. HSCT for lymphomas not in remission has poor results. In advanced-stage nasal, nonnasal, disseminated, or relapsed lymphomas, HSCT may be considered when remission is achieved. Prognostic modeling and EBV DNA monitoring may be useful in risk stratification for HSCT.