Survival Patterns in Patients with Relapsed or Refractory Diffuse Large B Cell Lymphoma: Treatment Trajectories and Responses after the First Relapse

Background: Nearly 40% of patients with diffuse large B-cell lymphoma (DLBCL) are either refractory to or relapse (R/R) after initial first-line (L1) treatment. These patients frequently receive subsequent lines of treatment, although to achieve long-term remission requires aggressive chemoimmunotherapy followed by autologous bone marrow transplant (BMT). Few real-world studies have examined the treatments used in R/R DLBCL patients over the entire disease trajectory. Methods: Using the VA Cancer Registry System and electronic healthcare records (EHR), we identified Veterans diagnosed with DLBCL between January 1, 2000 to December 31, 2016 who relapsed or progressed after L1 RCHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone ± rituximab) ± etoposide and then proceeded to receive at least one additional line of treatment. Human annotation of EHR notes confirmed DLBCL diagnosis, treatment regimen(s) received (including BMT), and treating physician response assessment after each line. Treatment regimens were classified as aggressive (with intent to proceed to BMT) or non-aggressive per National Comprehensive Cancer Network (NCCN) guidelines. Eligible patients were followed until loss to follow-up, death or the end of the study period (March 31, 2019). Patients with a cancer diagnosis other than DLBCL were excluded from the study. Results: We identified 270 R/R DLBCL patients who received a second-line (L2) treatment after having previously received L1 with RCHOP ± etoposide. The mean age of patients was 64.6 years; 97.4% of patients were male. Of the 270 patients, 166 (61.5%) patients received an aggressive L2 treatment regimen. RICE (ifosfamide, carboplatin, and etoposide ± rituximab) and BR (bendamustine ± rituximab) were the most commonly used aggressive and non-aggressive regimens, accounting for 39.3% and 8.9% of L2 treatment, respectively. Compared with patients who received non-aggressive L2 treatment, aggressive L2 treatment patients were younger (61.4 versus 69.7 years). Following aggressive L2 treatment, 87 patients (52.4%) achieved complete or partial response (CR/PR), while CR/PR was achieved in 43 (41.3%) patients who received non-aggressive L2. Of the 29 (10.7%) patients who received BMT, 28 received an aggressive L2 regimen. Approximately half of all patients who received L2 therapy (121/270) proceeded to third-line (L3) treatment, of which 47 (38.8%) received an aggressive L3 regimen. Nearly half of those patients who received a