Impact of delays in definitive treatment on overall survival: a National Cancer Database study of patients with Hodgkin lymphoma.

The purpose of this large observational study was to examine outcomes in patients with Hodgkin lymphoma (HL) by timing to definitive chemotherapy (TTC) using standard and propensity score (PS)-adjusted Cox proportional hazards models. From 1998-2011, 56,457 patients with stage I-IV HL were studied, with a median follow-up of 6.0 years (median age=39). Median TTC was 26 days from diagnosis. The cohort of "early" (<60 days from diagnosis) TTC patients included 45,307 (80.3%) patients and "late" (≥60 days) TTC was 11,150 (19.7%). Patients were more likely to experience early TTC if they were of a younger age, at an advanced stage, with "B" symptoms, favorably insured, favorable socioeconomic status, and treated at comprehensive cancer center (all p<0.05). Ten-year overall survival for patients with early TTC was 73.2% vs. 70.0% for those with late TTC (HR=0.87; 95%CI, 0.83-0.92, p<0.0001). After PS-matching for co-variates, early TTC was not associated with overall survival (HR=0.96; 95%CI, 0.85-1.08, p=0.51). This represents the only study to evaluate overall survival by time to definitive treatment for HL.