Promising clinical outcomes of sequential and “Sandwich” chemotherapy and extended involved‐field intensity‐modulated radiotherapy in patients with stage I E / II E 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.