High-dose chemotherapy with hematopoietic stem cell transplantation is effective for nasal and nasal-type CD56+ natural killer cell lymphomas

CD56(+) natural killer (NK) cell lymphomas occur frequently in the nasal and nasopharyngeal regions and carry a poor prognosis. We have studied seven cases with NK-cell lymphomas. These lymphomas showed the following immunophenotype: CD56(+), CD2(+), sCD3(-) and Epstein-Barr virus-encoded small RNAs (EBERs)(+). Six patients had localized (stage I or II) disease involving the nasopharyngeal region, while one had stage III disease. One patient with stage I disease achieved a complete remission (CR) after treatment with involved-field irradiation, but subsequently relapsed and died. The remaining six patients received combination chemotherapy as primary treatment: five patients with localized stage I or II disease and one patient with advanced stage III disease. Responses to initial chemotherapy were generally poor. These six patients received a variety of salvage chemotherapy regimens, but never achieved a CR. Subsequently, four of six patients showed a highly aggressive clinical course and died of disseminated disease within 1 year from the diagnosis. Three of six patients received high-dose chemotherapy supported by syngeneic, autologous or allogeneic peripheral blood stem cell transplantation. Two of the three transplant patients achieved a CR and are now surviving in continuous CR. Our clinical experience suggests that myeloablative high-dose chemotherapy and bone marrow rescue by hematopoietic stem cell transplantation may be an effective salvage treatment modality for refractory NK-cell lymphomas and could be considered as a part of the initial therapy for these patients.