In all patients subgroups (gender, age, age adjusted IPI, Ann Arbor stage, ECOG, β 2 microglobulin, LDH, albumin, B symptoms, bulky disease, extranodal sites, bone marrow involvement), the risk ratios for event-free survival and overall survival (R-CHOP compared with CHOP) were less than 0.83 and 0.95 respectively.