AUTOLOGOUS HEMATOPOIETIC CELL TRANSPLANTATION FOR PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA (PCNSL). REAL‐WORLD REPORT OF POLISH LYMPHOMA RESEARCH GROUP.

Introduction: High-dose chemotherapy with autologous stem-cell transplantation (HDC-ASCT) is now the preferred consolidation strategy for young PCNSL patients. The optimal conditioning regimen unknown. data suggests that BEAM (carmustine, etoposide, cytarabine, melphalan) ineffective, BCNU/TT (carmustine/thiotepa) well-tolerated treatment related mortality (TRM) 1%–3%, but late relapses are common, and TBC (thiotepa, busulfan, cyclophosphamide) highly effective higher TRM 11%. Methods: aim of study was to analyze safety efficacy based on consisted carmustine, etoposide thiotepa (BET)1 followed by ASCT. We evaluated outcome 45 immunocompetent adult patients treated in 4 Polish centers between Feb. 2015 Oct. 2022. Six cycles induction rituximab, methotrexate (3.5 g/m2), ifosfamide vincristine (R-MIV) one cycle cytarabine (AT)2 were given. Patients a complete or partial response (CR/PR) proceeded carmustine 400 mg/m2 day -5, 150 -5,-4, -3, 5 mg/kg every 12 h days -4 -3 (total doses), Results: Median age (range) transplanted 57 years (19-66) 15 (33%) ≥60 old. At end 29 (64.5%) obtained CR/CRun (19/10 respectively), additional (11%) no evidence disease at baseline, 11 (24.5%) PR, standard CT/MRI assessment. For 32 (71%) 18FDG PET/CT done before ASCT, metabolic-CR confirmed. Mean number 584.4 (187–2642) × 106 CD34+ peripheral blood stem cells collected, corresponding 7.2 cells/kg (2.55–34.7 cells/kg). hospitalization time from ASCT days. hematologic recovery PLT > 25 G/L NEU 0.5/ 1.0 9 9/10 days, respectively. most common grade 3–4 non-haematological toxicities diarrhea (12 patients, mean days) mucositis (18 days). Febrile neutropenia occurred 21 (mean 2.5 Blood cultures did not reveal any relevant pathogens except patient confirmed Enterobacter cloacae-ESBL Klebsiella oxytoca. Two (TRM 4.4%) died transplant-related complications: septic shock neurotoxicity. median follow-up 41 (13-92) months, 3-year progression free survival (PFS) overall (OS) 78% (95% CI: 65-91) 81% 68-93). Relapse all within first months after Causes death were: lymphoma (n = 6), 2), accident 1) concomitant diseases 2). Keywords: aggressive B-cell non-Hodgkin lymphoma, cell transplant No conflicts interests pertinent abstract.