We aimed to determine the survival benefits of chemotherapy (CT) additional to radiotherapy (RT) in different risk groups of patients with early-stage extranodal nasal-type NK/T-cell lymphoma (ENKTCL) and to investigate the risk of postponing RT based on induction CT responses. A total of 1360 patients who received RT with or without new-regimen CT from 20 institutions were retrospectively reviewed. The patients had received RT alone, RT followed by CT (RT+CT), or CT followed by RT (CT+RT). The patients were stratified into different risk groups using the nomogram-revised risk index (NRI). A comparative study was performed using propensity score-matched (PSM) analysis. Adding new-regimen CT to RT (versus RT alone) significantly improved overall survival (OS, 73.2% vs. 60.9%, P < 0.001) and progression-free survival (PFS, 63.5% vs. 54.2%, P < 0.001) for intermediate-/high-risk patients, but not for low-risk patients. For intermediate-/high-risk patients, RT+CT and CT+RT resulted in non-significantly different OS (77.7% vs. 72.4%; P = 0.290) and PFS (67.1% vs. 63.1%; P = 0.592). For patients with complete response (CR) after induction CT, initiation of RT within or beyond three cycles of CT resulted in similar OS (78.2% vs. 81.7%, P = 0.915) and PFS (68.2% vs. 69.9%, P = 0.519). For patients without CR, early RT resulted in better PFS (63.4% vs. 47.6%, P = 0.019) than late RT. Risk-based, response-adapted therapy involving early RT combined with CT is a viable, effective strategy for intermediate-/high-risk early-stage patients with ENKTCL in the modern treatment era. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.