Allogeneic haematopoietic stem cell transplantation as a salvage strategy for relapsed or refractory nasal NK/T-cell lymphoma

Nasal NK/T-cell lymphoma is rare and occurs most frequently in East Asia and Latin America. It is characterized by its aggressive nature and tends to become resistant to chemotherapy and radiotherapy. Autologous haematopoietic stem cell transplantation (auto-HSCT) is often associated with a high relapse rate for the active or disseminated disease. There are limited data about allogeneic haematopoietic stem cell transplantation (allo-HSCT) for relapsed or refractory nasal NK/T-cell lymphoma. In our study, two patients with nasal NK/T-cell lymphoma were successfully treated with allo-HSCT. The first patient was a 31-year-old woman who relapsed after auto-HSCT. Subsequently, HLA-matched allo-HSCT was considered as a salvage treatment. Modified BU/CY conditioning regimens included BU/CY/Vm26/Ara-C. Donor lymphocyte infusion was used to reduce the risk of relapse. After allo-HSCT, the tumor in her nasal cavity gradually disappeared. She has been in continuous complete remission (CR) for 3 years. The second patient was a 26-year-old woman diagnosed with stage IIIB advanced nasal NK/T-cell lymphoma who was resistant to combination radiochemotherapy. She underwent HLA-matched allo-HSCT as a salvage treatment. Modified BU/CY conditioning regimens included BU/CY/MeCCNu/Ara-C. She has been in continuous CR for five years. The stem cell source was peripheral blood for both patients, and there was no severe graft-versus-host disease in either patient. Our clinical experience suggests that allo-HSCT with a modified conditioning regimen is a promising treatment for patients with relapsed or refractory nasal NK/T-cell lymphoma.