Diagnosis-to-Treatment Interval Reflects Clinical Urgency and Disease Burden in T-Lymphoblastic Lymphoma: A Multicenter Cohort Study

Objective: Diagnosis-to-treatment interval (DTI) has been investigated in several lymphoma subtypes, but its significance in T-lymphoblastic lymphoma (T-LBL) remains unclear. We evaluated whether DTI reflects clinical urgency, disease burden and early outcomes in newly diagnosed T-LBL. Methods: We retrospectively analyzed 220 patients with newly diagnosed, mass-dominant, and histologically diagnosed T-LBL treated at four centers between 2003 and 2025. DTI was operationally defined as the interval from diagnostic biopsy to first systemic anti-lymphoma therapy and was primarily analyzed as a continuous variable per 7-day increase. Descriptive DTI groups were <15, 15–29 and ≥30 days. Results: Median DTI was 20 days (interquartile range [IQR], 14–32). Shorter DTI was associated with advanced stage, elevated lactate dehydrogenase (LDH), multiple extranodal involvement, central nervous system (CNS) involvement, B symptoms, lower hemoglobin and higher International Prognostic Index (IPI) score. CNS involvement remained independently associated with DTI < 15 days. In adjusted analyses, each 7-day increase in DTI was associated with lower odds of early treatment failure within 2 years (odds ratio [OR] 0.72, 95% confidence interval [CI] 0.58–0.88), lower hazards of progression-free survival (PFS) events (hazard ratio [HR] 0.84, 95% CI 0.74–0.94) and lower mortality (HR 0.84, 95% CI 0.73–0.98), but not complete response. Conclusions: Shorter DTI appears to reflect clinical urgency and disease burden rather than a causal effect of early treatment.