Background Up to now no real world data on the diagnostic work-up and treatments of diffuse large B-cell lymphoma (DLBCL) in Belgium were available. Aims To determine the patterns of care for DLBCL in Belgium with a specific focus on the elderly population, patients with comorbidities and other tumors (12%). Methods Coded data of all adult (≥ 20 year) DLBCL diagnosed 2013-2015 (n=1,890) were obtained via the Belgian Cancer Registry. Vital status was available until 1/7/2019. Data was extracted from pathology reports (10 biomarkers from IHC – FISH) and oncological care programs (performance status – staging). Treatments were inferred from health insurance data of reimbursed drugs. Information on HSCT and radiotherapy was based on nomenclature codes. An in-house algorithm was set up to define: Chemotherapy regimen (e.g. R-CHOP/R-DHAP) Number of cycles and cycle interval Switch between regimen Results Overall survival: The 2-year OS of all patients was 63.07% with a clear influence of age (30-84%). In contrast to the IPI using 60 as a cut-off, survival changed more markedly after the age of 70. Biomarkers: Pathology subtyping in 2013-2015 was missing information on now deemed essential biomarkers in 10-85% of cases. Of the evaluable cases, 49% were double expressors and 10% were double-hit DLBCL (FISH performed in only ±10%). No major differences were observed between age groups. Treatments: These varied significantly by age group and are displayed in Figure 1. Systemic treatment was started in 84%, decreasing with age to only 43%. Anthracycline based regimens were most frequently used, even in the elderly, and gold standard R-(mini)CHOP was associated with the best 4y-OS of 76%. Radiotherapy alone was frequently (5-13%) used in the elderly, and associated with a worse survival. Nonetheless the 4y-OS of 38% suggests a cure for selected patients. Second line treatments were mostly platinum based and survival without an option for autologous HSCT (ASCT) was poor (5y-OS 65% (ASCT) vs 11% (no-ASCT)). ASCT within 2 ...