The Prognostic And Therapeutic Roles Of Primary Tumor Volume And Molecular Profile In Extranodal Nasal-type NK/T-cell Lymphoma

Part ⅠThe prognostic and therapeutic values of gross tumor volume in early-stage extranodal nasal-type NK/T cell lymphomaPurpose:This study aimed to investigate the prognostic value of gross tumor volume(GTV)in early-stage extranodal nasal-type NK/T-cell lymphoma(ENKTCL)treated with intensity-modulated radiation therapy(IMRT)and to explore the therapeutic value of GTVbased radiation dose and combined chemotherapy(CT).Methods and Materials:A total of 319 patients with early-stage ENKTCL who underwent IMRT were reviewed retrospectively.Overall survival(OS),progression-free survival(PFS),and locoregional control(LRC)were estimated using Kaplan-Meier method and compared using the log-rank test.The cumulative incidence of(Locoregional recurrence)LRR was calculated via competing risk analysis using the Gray’ test.Cox proportional hazards regression was performed to identify independent risk factors for survival outcomes.Penalized spline regression was used to flexibly model the association of continuous predictors(GTV and RT dose)with mortality,progression,and relapse.Receiver operating characteristic(ROC)curve analysis was used to define the optimal cutoff value of GTV.Inverse probability of treatment weighting(IPTW)was employed to balance the clinical baseline characteristics between the different treatment groups for the purpose of reducing selection bias.The prognostic value of adding chemotherapy to IMRT at different GTV sizes was analyzed and visualized by calculating the interact effect of GTV and CT on OS and PFS in COX proportional hazards model.Results:The median GTV volume was 29.3 ml and the mean GTV volume was 46 ml(range:0.3 to 480.7 ml).With a median follow-up of 70.6 months,the 5-year OS,PFS,and LRC for the entire cohort were 72.9%,64.4%,and 89.9%,respectively.The risk of disease mortality,progression,and recurrence increased steadily with increasing GTV.In multivariable analysis,GTV was an independent prognostic factor.Patients with small GTV(<35 ml)had significantly higher 5-year OS(83.0%vs.59.4%;P<0.001),PFS(76.7%vs.48.4%;P<0.001),and LRC(94.6%vs.82.6%;P=0.001),and lower 5-year cumulative LRR rate(5.4%vs.17.4%;P<0.001),than patients with large GTV(≥35 ml).The risk of LRR was low between RT doses of 50 Gy and 56 Gy,independent of GTV.For patients with large GTV(≥ 35 ml),dose≥56 Gy was not associated with decreased LRR.Patients with larger GTV could benefit more from combined chemotherapy.For patients with small tumor(GTV<35 ml),the combination of anthracyclines(ANT)or nonanthracycline(non-ANT)chemotherapy with IMRT added no additional survival benefit.Especially,the combination of ANT-contained chemotherapy regimens may have adverse effects on survival time.For patients with large tumor(GTV≥ 35 ml),combined chemotherapy significantly improved OS and PFS,and the survival benefit came only from non-ANT chemotherapy.Conclusion:Larger GTV is associated with poor survival and a high risk of LRR in earlystage ENKTCL patients treated with IMRT.A dose of 50-56 Gy may be appropriate to achieve satisfactory locoregional control,regardless of GTV.Patients with larger GTV might benefit more from additional chemotherapy,and should consider receiving a combined-modality therapy with non-ANT-based regimens.Part ⅡTranscriptomic and genomic analyses identified molecular subtypes and novel prognostic markers in extranodal nasaltype NK/T-cell lymphomaPurpose:Extranodal nasal-type NK/T-cell lymphoma(ENKTCL)encompasses a rare and aggressive subtype of non-Hodgkin lymphoma with high clinical and genetic heterogeneity.Research exploring the molecular mechanisms and prognostic molecular factors of ENKTCL remains limited.In this study,we sought to investigated molecular subtypes and potential prognostic biomarkers of ENKTCL,and expected to provide a theoretical basis for refining risk stratification and developing therapeutic targets for ENKTCL.Methods and materials:71 samples from newly diagnosed ENKTCL in our institution were collected and subjected to transcriptomic sequencing.Of them,65 samples were also subjected to genomic sequencing.Non-negative matrix factorization(NMF)was used to identify distinct molecular subtypes.R package of "limma" was applied to calculate the differentially expressed genes(DEGs)between subtypes.GO/KEGG and GSEA analysis were used to depict the underlying function candidate genes.ssGSEA and ESTIMATE algorism were performed to evaluate the immune infiltration for each sample.The molecular prognostic model was constructed through LASSO-Cox regression analysis and validated in the external cohort GSE90597.The ROC analysis was used to evaluate the model prediction accuracy.Results:Based on gene expression profiles,two distinct molecular subtypes were identified.Clinical characteristics and treatment between the two subtypes were comparable.The C1 subtype(defined as high-risk subtype)had worse overall survival(OS)and progression-free survival(PFS)compared to C2 subtype(low-risk subtype).Integrated transcriptomic and genomic analysis revealed that C1 subtype was characterized by frequent mutation of DDX3X,TP53 and JAK/STAT pathway gene,and activation of proliferation related signaling pathway,as well as immunosuppression.Among them,TP53 mutation and JAK/STAT mutation were associated with poor prognosis in our cohort.C2 subtype lacks the above characteristics,mainly manifested as high frequency of KMT2D mutation.A 5-gene risk model(including MND1,KRT81,IL10,FCAR and DMBT1)was established and validated in an external cohort.The poor prognosis was associated with high expression of MND1,KRT81,IL10,and FCAR but low expression of DMBT1.The risk score(RS)based on the above 5 genes could effectively distinguish patients’ prognosis.The AUC for predicting 5-year OS were 0.869 in the training set and 0.760 in the validation set,respectively.Conclusion:This study identified two molecular subtypes of ENKTCL with distinct prognosis,and depicted the underlying mechanisms of the high-risk subtype(C1 subtype).Besides,we provided a robust and reliable gene signature that had significant implications in the prediction of OS of ENKTCL patients.The results of this study broadened the insights on the genetic heterogeneity and molecular mechanisms of ENKTCL,and might help developing more effective molecular risk stratification as well as targeted therapy strategies for ENKTCL...