Promising clinical outcomes of sequential and "Sandwich" chemotherapy and extended involved-field intensity-modulated radiotherapy in patients with stage I /II 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 /II extranodal ENKTL, nasal-type.

Methods: One hundred and fifty-five patients with stage I /II 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 disease, and 61 patients had stage II 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 /II ENKTL patients.