Upfront radiation is essential for high-risk early-stage extranodal NK/T-cell lymphoma, nasal type: comparison of two sequential treatment modalities combining radiotherapy and GDP (gemcitabine, dexamethasone, and cisplatin) in the modern era.

Early/upfront radiation was associated with improved survivals compared with late radiation for early-stage NK/T-cell lymphoma (NKTCL) in the old era when anthracycline-base chemotherapy (CT) prevailed. However, in the modern era of effective l-asparaginase/gemcitabine-based CT, the optimal timing of radiation is unclear. In this study, 75 patients with newly diagnosed NKTCL, who were treated with combined involved-field intensity-modulated radiotherapy and GDP (gemcitabine, dexamethasone, and cisplatin) were retrospectively reviewed, including 45 from the RT + CT group and 30 from the CT + RT ± CT group. Compared with CT + RT ± CT, RT + CT sequence achieved superior progression-free survival (5-year PFS: 81.6% vs. 56.0%, p = .017) and locoregional control (LRC) (90.8% vs. 66.9%; p = .020). Responses, overall survivals or adverse event incidences did not differ across the groups. Upfront RT was a powerful prognostic variable for favorable PFS (HR 0.302; 95% CI: 0.125-0.729; p = .008). It indicated that upfront RT administration remains vital in enhancing LRC and survival for localized NKTCL in the modern era.