Introduction. Diffuse large B-cell lymphoma (DLBCL) is a clinically heterogeneous disease in which current prognostic models do not fully capture outcome variability. Systemic inflammation has been implicated in tumor progression and resistance to therapy. Hemogram-derived inflammatory indices have been proposed as accessible prognostic markers; however, their relative performance and clinical utility remain inconsistent.

Objective. To evaluate the association between inflammatory indices and clinical outcomes in DLBCL and to identify those with the most relevant prognostic value.

Methods. This retrospective, single-center longitudinal study included 107 adult patients with histologically confirmed DLBCL treated at Sanatorio Allende (Córdoba, Argentina) between 2010 and 2023. Clinical and laboratory variables, including R-IPI, LDH, and complete blood count, were collected at diagnosis. Inflammatory indices analyzed included neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII; platelets × neutrophils / lymphocytes), and systemic inflammatory response index (SIRI; neutrophils × monocytes / lymphocytes). Associations with primary refractory disease, progression-free survival (PFS), and overall survival (OS) were assessed using univariate analysis. ROC curves were used to determine optimal cutoff values.

Results. Among 107 patients, 58% were male, with a mean age of 49 years. High-risk R-IPI was observed in 64% and elevated LDH in 52%. Primary refractory disease occurred in 32% of patients, and median OS was 49 months. Among the evaluated indices, NLR and SIRI showed the most consistent associations with clinical outcomes. An NLR >3.67 was associated with increased mortality (p=0.01), with an AUC of 0.649 and a hazard ratio of 2.61. Higher NLR values (>5.45) were associated with relapse with high specificity (91%). A SIRI >2257 was associated with worse OS (p<0.001), with an AUC of 0.66, 66% sensitivity, and 73% specificity. In contrast, LMR, PLR, and SII did not show significant associations with outcomes, although trends toward higher values were observed in patients with adverse clinical features.

Conclusions. In this cohort, NLR and SIRI showed consistent associations with survival and relapse, whereas other inflammatory indices demonstrated limited prognostic value. These findings suggest that selected inflammation-based indices may provide additional prognostic information beyond standard clinical factors; however, further studies are required to validate their role in risk stratification.