Reassessment of the prognostic value of the International Prognostic Index and the revised International Prognostic Index in patients with diffuse large B-cell lymphoma: A multicentre study

The International Prognostic Index (IPI) is a widely accepted model that is used to predict the prognosis of patients with diffuse large B-cell lymphoma (DLBCL) who are treated using chemotherapy. However, the prognostic value of the IPI has been a focal point of debate in the immunochemotherapy era. The aim of this study was to reassess the value of the IPI and revised IPI (R-IPI) in a Chinese population. A multicentre retrospective analysis of DLBCL patients who were treated with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP)-like chemotherapy alone or chemotherapy plus rituximab (R-CHOP-like) was performed. The prognostic values of IPI and R-IPI at the time of diagnosis with respect to overall survival (OS) and progression-free survival (PFS) were evaluated. Among the 438 patients in the study, 241 received a CHOP-like regimen and 197 patients received an R-CHOP-like regimen. Although the IPI remained predictive for the CHOP-like group, it failed to distinguish between the various prognostic categories in the R-CHOP-like group. Notably, redistribution of the IPI factors into R-IPI factors identified three discrete prognostic groups with significantly different outcomes in both the CHOP-like and R-CHOP-like groups. In the R-CHOP-like group, these three risk groups, very good, good and poor, had distinctly different 3-year PFS rates of 96, 84.3 and 67.5% (P=0.001), and 3-year OS rates of 96, 87.6 and 71.1% (P=0.003), respectively. Our study demonstrates the power of the R-IPI as a simplified and more clinically relevant predictor of disease outcome than the standard IPI in DLBCL populations in the rituximab era. Therefore, the R-IPI merits further study in a larger population-based prospective study.