Consolidative Treatment after Salvage Chemotherapy Improved Prognosis in Patients with Relapsed Extranodal Natural Killer/T-Cell Lymphoma

The optimal treatment strategy and prognosis for patients with relapsed natural killer/T-cell lymphoma (NKTCL) remain largely unknown. The treatment modalities and prognosis of fifty-six patients with relapsed NKTCL were retrospectively reviewed. Twenty-three (41.1%) patients had locoregional relapse alone, while 33 (58.9%) had distant with or without locoregional relapse. Chemotherapy was the initial salvage treatment, followed by radiotherapy (RT) or autologous hematopoietic stem cell transplantation (AHSCT) as consolidative therapy, depending on the status of remission and the pattern of relapse. The 5-year overall survival (OS) after relapse was 41.4% for the entire cohort. Complete remission (CR) after salvage treatment was associated with a substantially better survival (5-year OS after relapse: 74.7 vs. 7.8%, P < 0.001). For patients with locoregional relapse alone, consolidative RT after response to salvage chemotherapy significantly improved prognosis compared with follow-up (5-year OS: 83.3 vs. 41.7%, P = 0.047). For patients with distant relapse, the addition of consolidative AHSCT after response to chemotherapy significantly prolonged survival than follow-up (2-year OS: 100.0 vs. 20.0%, P = 0.004). Patients without consolidative treatment after response to salvage chemotherapy had a comparable survival to those who experienced stable or progressive disease after chemotherapy, regardless of the relapse pattern. Asparaginase (ASP)-containing salvage chemotherapy failed to convey a survival advantage over ASP-absent chemotherapy (5-year OS: 44.2 vs. 39.3%, P = 0.369). Patients who received ASP-containing chemotherapy in the first-line treatment had a poorer response to salvage chemotherapy and worse prognosis after relapse, compared with those receiving ASP-absent first-line chemotherapy. Consolidative RT or AHSCT improved prognosis in patients with relapsed NKTCL who responded to initial salvage chemotherapy. The role of ASP in salvage chemotherapy after relapse required further exploration in prospective studies.