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.