BackgroundFew clinical studies have clarified the prognostic factors that affect clinical outcomes forpatients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) afterimmunochemotherapy. MethodsA total of 158 patients with relapsed or refractory DLBCL were enrolled. All patients underwentpositron emission tomography/computed tomography (PET/CT) before and aftersalvage therapy. All enrolled patients previously received the ifosfamide, carboplatin, andetoposide regimen. Clinical outcomes were compared according to several factors (age ≥ 65 years, low age-adjusted International Prognostic Index [aa-IPI], maximum standardizeduptake value [SUVmax] ＜6.0 on PET/CT, time to relapse ≥12 months, completeresponse after salvage therapy). A low aa-IPI, SUVmax ＜6.0, and time to relapse ≥ 12months were independent prognostic factors for survival. ResultsIn univariate analysis and multivariate analysis, SUVmax below 6.0 (P＜0.001 for progression-free survival (PFS), P＜0.001 for overall survival (OS)) and low aa-IPI (P＜0.001for PFS, P＜0.001 for OS) were independent prognostic factors associated with favorableoutcome. ConclusionThe aa-IPI and initial SUVmax were powerful prognostic factors in patients with relapsedor refractory DLBCL.