Immunochemotherapy with rituximab and overall survival in patients with indolent or mantle cell lymphoma: A systematic review and meta-analysis

Background Addition of the anti-CD20 monoclonal antibody rituximab to chemotherapy (R-chemo) has been shown to improve response rates and progression-free survival in patients with indolent or mantle cell lymphoma. However, the impact of R-chemo on overall survival is unclear, We performed a comprehensive systematic review and meta-analysis to examine the efficacy of combined immunochemotherapy using R-chemo compared with the identical chemotherapy alone with respect to overall survival in patients with advanced indolent lymphoma or mantle cell lymphoma. Methods Medical databases and conference proceedings were searched for randomized controlled trials published from January 1990 through December 2005 that compared R-chemo with chemotherapy alone in patients with newly diagnosed or relapsed indolent lymphoma or mantle cell lymphoma. We included full-text and abstract publications. Endpoints were overall survival, disease control, overall response, and toxicity. A fixed-effects model was assumed in all meta-analyses. For binary data, the relative risk was used as an indicator of treatment effect, and the Mantel-Haenszel method was used to pool relative risks. Statistical tests for heterogeneity were one-sided; statistical tests for effect estimates were two-sided. Results Seven randomized controlled trials involving 1943 patients with follicular lymphoma, mantle cell lymphoma, or other indolent lymphomas were included in the meta-analysis. Five studies were published as full-text articles, and two were in abstract form. Patients treated with R-chemo had better overall survival (hazard ratio [HR] for mortality = 0.65; 95% confidence interval [Cl] = 0.54 to 0.78), overall response (relative risk of tumor response = 1.21; 95% Cl = 1.16 to 1.27), and disease control (HR of disease event = 0.62; 95% Cl = 0.55 to 0.71) than patients treated with chemotherapy alone. R-chemo improved overall survival in patients with follicular lymphoma (HR for mortality = 0.63; 95% Cl = 0.51 to 0.79) and in patients with mantle cell lymphoma (HR for mortality = 0.60; 95% Cl = 0.37 to 0.98). However, in the latter case, there was heterogeneity among the trials (P =.07), making the survival benefit less reliable. Conclusion In patients with indolent or mantle cell lymphoma, R-chemo is superior to chemotherapy alone with respect to overall survival.