ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR PATIENTS WITH AGGRESSIVE NATURAL KILLER CELL LEUKEMIA: A NATIONWIDE MULTICENTER ANALYSIS IN JAPAN

Abstract

just 0.3% in North American and European countries). The prognosis for patients (pts) with advanced or refractory ENKL is extremely poor. The role of allogeneic transplantation (alloSCT) has been explored in a few small retrospective studies, which almost exclusively were comprised of Asian patients. Here, we describe the case report of pt with refractory ENKL successfully treated with haploidentical transplantation (haploSCT) and provide the analysis of ENKL in Caucasian pts using the observational database of the Czech Lymphoma Study Group (CLSG). Case report: A 35-year-old woman was referred to our department with 6 years history of autoimmune granulomatosis (repeated biopsy from mouth), last biopsy from the right vestibule diagnosed ENKL. PET CT scan showed involvement of gingiva, face and one mediastinal lymph node. Pt was treated with 4 cycles of chemotherapy (CHOEP), after the initial improvement the progression of ENKL on the tongue was histologically verified. Salvage chemotherapy DHAP was started with subsequent progression after the first cycle. The 3rd line chemotherapy DeViC (2 cycles) was administered only with a partial transient effect and early recurrence of lymphoma infiltration. Radiotherapy of soft facial tissues was performed with complete regression of infiltrates. However early after the radiotherapy 2 new FDG accumulating lesions in spleen were detected. Early haploSCT was performed (donor haploidentical brother, reduced intensity conditioning). 1 year after the haploSCT pt is alive in complete remission of ENKL. Further we analyzed the group of pts with ENKL from CLSG database. 40 adult (≥18 years) pts with ENKL were reported to the CLSG database between 1999 and 2018. The median age at the time of diagnosis was 52 years (range: 21–86); 62% were male and 74% had ECOG 0-1. Therapy was known for 37 pts; 18 (49%) received only chemotherapy (mostly CHOP and CHOEP), 2 (5%) radiation alone, and 17 (46%) received combined radiation and chemotherapy. 19 pts (52%) responded after the first line treatment; 16 pts (43%) achieved CR and 3 pts (8%) PR, 6 pts. (16%) were not evaluable and 12 pts (32%) had primary progressive disease. 10-years probability of OS of the whole group was 38%, RFS 27%. 7 pts from progressive disease group received second line chemotherapy with subsequent further progression, 1 pt underwent alloSCT and achieved complete remission. Except for the patient after alloSCT all pts died from disease progression. Discussion: alloSCT should be considered for high-risk or advancedstage patients in remission or relapsed/refractory ENKL. However, reports of alloSCT for ENKL are limited because of the rarity of the disease. GovTrial Number: NCT03199066.