Comparison of OS between RT + CT, RT alone and CT + RT for high-risk early-stage patients. OS for high-risk patients with early-stage NKTCL after RT + CT or RT alone before (A) and after match (B) stratification; OS after RT + CT and CT + RT before (C) and after (D) match stratification; and OS after RT alone and CT + RT before (E) and after (F) match stratification.