Clinical impact of induction treatment modalities and optimal timing of radiotherapy for the treatment of limited-stage NK/T cell lymphoma

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.

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.

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.

Prognostic Nomogram for Overall Survival in Early Stage Extranodal Natural Killer/T Cell Lymphoma Treated With High-Dose Radiotherapy

BACKGROUND

The aim of this study was to develop a prognostic nomogram for early stage extranodal natural killer/T-cell lymphoma, nasal type (ENKL) treated with high-dose radiotherapy (RT).

PATIENTS AND METHODS

A total of 81 patients at 2 cancer centers with stage I to IIE ENKL who received chemotherapy (CT) and high-dose RT were retrospectively analyzed. The development of the nomogram was on the basis of the Cox proportional hazards model. We implemented the concordance index (C-index) and performed a calibration curve to determine its predictive and discriminatory capacity and compared our nomogram with the International Prognostic Index (IPI) and the Korean Prognostic Index (KPI).

RESULTS

The nomogram included 4 important variables and used a multivariate analysis: lactate dehydrogenase, primary tumor invasion, tumor response, and CT regimen. The 5-year OS rate and progression-free survival were 64.7% and 57.5%, respectively for the entire group. The C-index of the nomogram for overall survival (OS) prediction was 0.87, and it was superior to the predictive power of the IPI and KPI. The calibration curve showed that the nomogram accurately predicted the 5-year OS.

CONCLUSION

The proposed nomogram could provide an individualized risk estimate of the OS for early stage ENKL treated with CT and high-dose RT.

Nasal NK/T cell lymphoma mimicking mucosa-associated lymphoid tissue lymphoma in morphology: A case report

The objective of the present study was to describe the clinicopathological features of a patient with nasal NK/T cell lymphoma that was similar in morphology to mucosa-associated lymphoid tissue lymphoma (MALToma). The clinicopathological data of a patient diagnosed with nasal NK/T cell lymphoma mimicking MALToma was collected, and the clinicopathological characteristics were discussed. The female patient was 43 years old and had suffered from persistent congestion for ten days. The mucosa in the left nasal cavity was inflamed, resulting in congestion and it was also purulent on the surface, as observed by nasal endoscopy. The disease was considered to be inflammatory based on CT scan. A biopsy after operation showed that the tumor consisted of small lymphoid cells that resembled MALToma in morphology. On the basis of the immunohistochemistry and in situ hybridization laboratory tests, a diagnosis of left nasal NK/T cell lymphoma was made. The patient received chemotherapy and radiotherapy, and remission was achieved six months after diagnosis. The patient was in a good condition at 16 months follow-up. In conclusion, NK/T cell lymphoma composed of small cells may be a type of indolent lymphoma with special characteristics of clinical presentation, image, pathology and prognosis. This case highlights that more attention is required by radiologists, pathologists and hematologists to diagnose this type of lymphoma.

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.

The optimal timing of radiotherapy in the combined modality therapy for limited-stage extranodal NK/T cell lymphoma (ENKTL): a systematic review and meta-analysis

The optimal timing and sequencing of radiotherapy (RT) and chemotherapy (CT) in the treatment of limited-stage extranodal NK/T cell lymphoma (LS-ENKTL) has not been elucidated. The aim of this meta-analysis was to evaluate whether the timing of RT in relation to CT affects the survival of patients with LS-ENKTL. We searched Medline, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Clinicaltrials.gov , and relevant meeting abstract databases from inception through April 2018 without age or language restrictions. Studies comparing upfront RT plus CT with induction CT followed by RT in patients with LS-ENTKL were eligible for inclusion. Seven studies with 1593 patients were included, and all were retrospective cohort studies. Compared with induction CT followed by RT, upfront RT significantly improved OS of patients with LS-ENTKL (HR = 0.70, 95%CI 0.55-0.88, P = 0.002), with no evidence of heterogeneity across studies (I² = 0%). In subgroup analyses, the beneficial effect of upfront RT on survival did not differ significantly between subgroups of studies with different types of chemotherapy regimens (anthracycline-based or non-anthracycline-based), the administration of concurrent chemoradiotherapy or not, and different median doses of RT (≥ 45 or < 45 Gy). These results suggest that upfront RT plus CT confers survival advantage over induction CT followed by RT for the treatment of LS-ENTKL, and this survival advantage is not significantly affected by the types of CT regimens or timing of CT. Given the retrospective nature of included studies, these results should be interpreted with caution in clinical practice.

LEE011 and ruxolitinib: a synergistic drug combination for natural killer/T-cell lymphoma (NKTCL)

Natural killer/T-cell lymphoma (NKTCL) is an aggressive non-Hodgkin lymphoma that has been facing limited success with conventional treatments, urging for the discovery of alternative strategies. Recent studies including ours have revealed that EZH2 and JAK-STAT signalling pathways are key contributors to NKTCL pathogenesis. In particular, we found that EZH2 is overexpressed and directly transcriptionally activates the CCND1 gene to confer growth advantage. CCND1 codes for cyclin D1, which complexes with CDK4/6 to promote G1 to S phase transition. Therefore in this study we investigated whether inhibiting both JAK1/2 and CDK4/6, using LEE011 and ruxolitinib respectively is effective in NKTL. We first demonstrate that separate LEE011 and ruxolitinib treatment is sufficient to cause growth inhibition of NKTCL cells. More importantly, we found that there is synergistic growth inhibitory effects on NKTCL cells with combination treatment of LEE011 and ruxolitinib. The results obtained shows that the targeting of both CDK4/6 and JAK1/2 are promising to develop better treatment alternatives for NKTCL.

A Multicenter Retrospective Comparison of Sequential versus Sandwich Chemoradiotherapy for Stage IE-IIE Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type

Background: Chemotherapy and radiotherapy are critical for treating early-stage extranodal natural killer/T-cell lymphoma, nasal type (ENKTL); however, the optimal therapy sequence remains unclear. Therefore, we performed this study to compare the efficacy of L-asparaginase/pegaspargase-based sequential versus sandwich chemoradiotherapy for patients newly diagnosed with stage IE-IIE ENKTL.

Methods: Patients were categorized into sequential (N = 111) and sandwich (N = 104) groups. Chemotherapy regimens included GELOX, SMILE, and VLP. The median radiotherapy dose was 55.0 Gy (range, 40.0-63.0 Gy). Adverse events, treatment responses, and survival outcomes were analyzed.

Results: Patients' clinical characteristics were largely comparable between the 2 groups; however, the sandwich group comprised a larger number of Ann Arbor stage IIE patients. Local invasion was the most significant predictor of overall survival (OS); local invasion and Ann Arbor stage were significant predictors of progression-free survival (PFS). There were no significant differences in the complete response rate (85.6% vs. 89.4%, p = 0.396), 3-year OS (77.5% vs. 80.8%, p = 0.636), or 3-year PFS rates (74.8% vs. 76.9%, p = 0.806) in the sequential vs. sandwich groups, respectively. The incidence of grade 3/4 hematological toxicities was higher in the sandwich group than in the sequential group (27.9% vs. 15.3%, respectively, p = 0.025). The response rates and survival outcomes in stage IE and IIE patients did not differ between sequential and sandwich groups.

Conclusions: In the era of L-asparaginase/pegaspargase, both sequential and sandwich chemoradiotherapy are safe and similarly effective in patients with newly diagnosed stage IE-IIE ENKTL.