Impact of time from diagnosis to initiation of curative chemotherapy on survival of patients with diffuse large B-cell lymphoma (DLBCL).

8552 Background: DLBCL is potentially curable with combination chemotherapy such as CHOP-R. Although it is generally regarded appropriate to start chemotherapy promptly after diagnosis, the impact of the time from diagnosis to treatment initiation on treatment outcome is unknown. Methods: Patients diagnosed with DLBCL and treated with at least one cycle of CHOP-R with curative intent during 2003 – 2008 in British Columbia were identified in the Lymphoid Cancer Database. Additional demographic data were obtained from the BC Cancer Registry. The BC Cancer Agency provincial pharmacy database was used to obtain dates of chemotherapy administration. The impact of the time interval from the date of pathologic diagnosis to treatment on overall survival (OS) and progression-free survival (PFS) was evaluated. Results: A total of 793 patients were identified: 199 (25%) received CHOP-R <2 weeks after diagnosis, 244 (31%) at 2-4 weeks, 293 (37%) at 5-8 weeks, and 57 (7%) at >8 weeks. High international prognostic index, primary mediastinal DLBCL, and hospitalization at the time of CHOP-R start were associated with earlier initiation of chemotherapy (p<0.001 for all factors). Distance to chemotherapy from home (p=0.237), rural vs. urban location (p=0.952), geographic region (p=0.458), and median household income (p=0.127) were not associated to treatment start. Five-year PFS and OS respectively were 54% (SD 4%) and 61% (SD 4%) for treatment <2 weeks, 63% (SD 3%) and 66% (SD 3%) for 2-4 weeks, 70% (SD 3%) and 74% (SD 3%) for 5-8 weeks, and 60% (SD 7%) and for 61% (SD 8%) >8 weeks, p=0.006 (PFS) and p=0.024 (OS). A multivariate analysis demonstrated no significant difference between the groups. Conclusions: In a publicly funded healthcare system, earlier initiation of chemotherapy was strongly associated with poor prognostic factors, as well as inferior PFS and OS. The timing of chemotherapy initiation appears to be related to clinical factors instead of system or socioeconomic barriers. Notwithstanding the lack of detrimental outcomes in those commencing CHOP-R after 8 weeks, clinicians should endeavor to initiate curative chemotherapy as soon as possible after a diagnosis of DLBCL is established.