Background: In stage I/II natural killer (NK)/T-cell lymphoma, concurrent chemoradiotherapy (CCRT) had previously been shown to result in superior outcome compared with anthracycline-containing regimens, which have since been considered ineffective. The role of CCRT in comparison with approaches employing nonanthracycline-containing chemotherapy (CT) and sequential radiotherapy (RT) in such patients remains to be defined. Patients and methods: Three hundred and three untreated patients (207 men, 96 women
median age: 51, 18-86 years) with stage I/II NK/T-cell lymphoma who had received nonanthracycline-containing regimens were collected from an international consortium and retrospectively analyzed. Treatment included single modality (CT and RT), sequential modalities (CT+RT
RT+CT) and concurrent modalities (CCRT
CCRT+CT). The impact of clinicopathologic parameters and types of treatment on complete response (CR) rate, progression-free-survival (PFS) and overall-survival (OS) was evaluated. Results: For CR, stage (P=0.027), prognostic index for NK/T-cell lymphoma (PINK) (P=0.026) and types of initial treatment (P=0.011) were significant prognostic factors on multivariate analysis. On Cox regression analysis, ECOG performance score (P=0.021) and PINK-EBV DNA (PINK-E) (P=0.002) significantly impacted on PFS
whereas ECOG performance score (P=0.008) and stage (P&lt
0.001) significantly impacted on OS. For comparing CCRT6CT and sequential CT+RT, CCRT6CT patients (n=190) were similar to sequential CT+RT patients (n=54) in all evaluated clinicopathologic parameters except two significantly superior features (higher proportion of undetectable circulating EBV DNA on diagnosis and lower PINK-E scores). Despite more favorable pre-treatment characteristics, CCRT6CT patients had CR rate, PFS and OS comparable with sequential CT+RT patients on multivariate and Cox regression analyses. Conclusions: In stage I/II NK/T-cell lymphomas, when effective chemotherapeutic regimens were used, CCRT and sequential CT+RT gave similar outcome.