Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease, with often a high Ki-67 proliferation index. Prognosis is associated with lymphoma stage, lactate dehydrogenase level, and metabolic tumor volume. Thus, intuitively, time from symptom onset to diagnosis would be assumed to be essential for treatment outcome, but existing literature is conflicting.

This prospective study evaluated diagnostic pathways and their impact on treatment outcomes in 160 patients with DLBCL.

The mean time from symptom onset to treatment initiation (TST) was 146 days. Mean patient-associated delay from the onset of symptoms to the first healthcare contact was 54 days; mean time from symptoms to biopsy was 130 days; and from biopsy to treatment initiation was 19 days. Prolonged time from symptom onset to treatment (TST) > 3 months was associated with a higher International Prognostic Index (IPI) score, whereas prolonged time from biopsy to treatment initiation (TBT) > 2 weeks was associated with better performance status and a lower IPI score. Prolonged time from symptom onset to treatment initiation was not associated with progression-free survival (PFS). Prolonged time from symptom onset to diagnostic biopsy > 7 weeks implied inferior progression free survival in the whole study cohort (2 year PFS 89% vs. 74%, p = 0.012), as well as among patients with highly proliferating tumors with Ki67 > 70% (2 year PFS 93% vs. 63%, p < 0.001). Longer time from biopsy to treatment initiation (TBT) > 2 weeks implied better progression-free survival (PFS) in patients with low proliferating tumors (2 year progression-free survival (PFS) 25% vs. 87%, p = 0.032), respectively.