Comparison of Prognostic Indices in Japanese Patients with Diffuse Large B-cell Lymphoma in the Yonago Area

【Background】 Several prognostic indices for diffuse large B-cell lymphoma (DLBCL) have been developed. Which index is appropriate for Japanese patients with DLBCL treated in real-world practice is unknown. 【Methods】 The prognostic performances of the original international prognostic index (IPI), age-adjusted IPI, National Comprehensive Cancer Network-IPI, elderly IPI and revised IPI were compared using patients with DLBCL treated in a single institute in the Yonago area in Japan. 【Results】 From 2005 through 2015, 182 patients with de novo DLBCL were treated with chemotherapy in Tottori University Hospital; 154 (85%) patients received R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) although full dose was administered in 63 (35%) patients. The median age of the patients was 71 years (range 18 to 91). Three-year overall survival rate was 71.8% (95% CI, 64.1% to 78.2%). All indices significantly discriminate risk groups for overall survival of the patients (P < 0.001). Although no statistical difference of performance was found among these indices, the best scores of model fit/discrimination measures were beaten out by age-adjusted IPI, the simplest and three-factor model. 【Conclusion】 Age-adjusted IPI is still usable in real-world practice while a better predictive model is desired for Japanese patients with DLBCL.