Absolute Lymphocyte Count at the Time of Relapse Predicts Survival in Patients with Diffuse Large B-Cell Lymphoma.

The International Prognostic Index at the time of relapse (IPI-R) has been reported to predict clinical outcome in patients with relapsed diffuse large B-cell lymphoma (DLBCL) undergoing autologous stem cell transplantation (ASCT) [Jabbour et al, Leukemia & Lymphoma2005;46(6):861–867; Lerner et al, Biology of Blood and Marrow Transplant2006;13:486–492; and Costa et al, Bone Marrow Transplant2008;41:715–720]. The absolute lymphocyte count (ALC) has been reported as a prognostic factor for survival at diagnosis, during standard chemotherapy and at day 15 post-ASCT for multiple hematological malignancies; however, no reports have addressed whether ALC at the time of relapse (ALC-R) predicts survival. Thus, we assessed the prognostic significance of ALC-R in patients with relapsed DLBCL. To be included in the study, patients were required to have been diagnosed with relapsed DLBCL, have ALC values available from the time of relapse, and to be followed at Mayo Clinic, Rochester. From Feb 2,1987 until March 6, 2006, 121 DLBCL patients qualified for the study. The overall survival (OS) was measured from the time of relapse to the date of death or last follow-up and progression-free survival (PFS) was defined as the time from relapse to the time of progression, relapse, death, or last follow-up. The median age at relapse was 68 years (range:25–88 years) and the median ALC-R was 1.21 x 109/L (range: 0.33–5.99 x 109/L). The value of ALC-R ≥ 1.0 x 109/L was used for the analysis based on previous publications. The groups (ALC-R ≥ 1 or < 1 x 109/L) were balanced for the IPI-R (p=0.1), as well as for undergoing ASCT (p=0.4). Superior OS was observed in patients with an ALC-R ≥ 1.0 x 109/L (N = 76) [median OS: 27.5 months, 3 years OS rates of 42%] compared with patient with an ALC-R < 1.0 x 109/L (N =45) [median OS: 9.4 months, 3 years OS rates of 13%] (p <0.0001). Superior PFS was also observed in patients with an ALC-R ≥ 1.0 x 109/L (N = 76) [median PFS: 14.8 months, 3 years PFS rates of 30%] compared with patient with an ALC-R < 1.0 x 109/L (N =45) [median PFS: 6.2 months, 3 years PFS rates of 11%] (p <0.001). ALC-R was an independent prognostic factor for OS [RR = 0.551, p < 0.009] and PFS [RR = 0.674, p < 0.02] in the multivariate analysis when compared with the IPI-R and whether patients underwent ASCT or not. Our study supports the hypothesis that ALC at relapse predicts clinical outcome in DLBCL and suggests that patient host immunity is an important variable predicting survival in relapsed DLBCL.