A systematic review and meta-analysis of rituximab-based immunochemotherapy for subtypes of diffuse large B cell lymphoma

Addition of rituximab to chemotherapy (R-chemo) has been shown to improve overall survival (OS) in patients with diffuse large B cell lymphoma (DLBCL). Germinal center B cell-like (GCB) subtype of DLBCL has a significantly better clinical outcome than those with non-germinal center B cell-like (non-GCB) subtype. Further research is needed to confirm this difference between those two subtypes treated with R-chemo. We searched for randomized controlled trials that compared R-chemo with identical chemotherapy alone in patients with newly diagnosed or relapsed DLBCL. A random versus fixed effects model was selected according to heterogeneity. Six eligible trials involving 748 adult patients were included in this meta-analysis. Fixed-effects analysis showed OS to be superior for the GCB patients treated with R-chemo (relative risk (RR) = 1.16, 95% confidence interval (CI) = 1.03–1.31, P = 0.02). Superiority was also observed for the GCB subtype under R-chemo with respect to disease control (RR = 1.16, 95% CI = 0.99–1.36) and overall response (RR = 1.19, 95% CI = 0.99–1.99). Both subtypes showed an increased OS (RR = 1.30, 95% CI = 1.11–1.51; RR = 1.89, 95% CI = 1.52–2.35, respectively) and disease control rate (RR = 1.27, 95% CI = 1.05–1.54, P = 0.01; RR = 2.21, 95% CI = 1.68–2.90, respectively) following R-chemo. Therefore, treated with R-chemo, GCB patients still has a significantly better clinical outcome than those with non-GCB subtype.