The Kyoto Prognostic Index for patients with diffuse large B-cell lymphoma in the rituximab era

The International Prognostic Index (IPI; age, the disease stage according to the Ann Arbor system, serum lactate dehydrogenase (LDH), Eastern Cooperative Oncology Group (ECOG) performance status (PS) and the presence of extranodal involvement (ENI)) has been the traditionally utilized prognostic tool for diffuse large B-cell lymphoma (DLBCL) treated with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) or CHOP-like chemotherapy. 1 Although the incorporation of rituximab (Rit) into CHOP has markedly improved the treatment outcome of DLBCL, this resulted in the reduction of the prognostic impact of the IPI. Even with the alternative revised IPI (R-IPI), it also failed to accurately identify the small proportion of patients at risk for a short survival period. Indeed, in the R-IPI-defined poor-risk group, ~40% of the patients survived for a relatively short period within 2 years, whereas more than half were cured by R-CHOP, indicating that the sensitivity of R-IPI-defined poor-risk group for identifying the potential short survivors was <50%. 2 More recently, the National Comprehensive Cancer Network (NCCN)-IPI has been proposed for DLBCL that emphasizes the prognostic values of age, high-serum LDH and the specific sites of ENI. 3 However, the NCCN-IPI was again not sufficient for discriminating patients at risk for very short survival, and this was also the case with other indexes, such as the modified Glasgow Prognostic Score (mGPS) consisting of serum C-reactive protein (CRP) and albumin (ALB) levels for DLBCL. 4 , 5 In addition, although informative, the prognostic prediction of DLBCL on the basis of biological features using either an immunohistochemical method or gene expression profiling remains difficult to be generally adapted in daily clinical practice. 6 , 7