Comparison of international prognostic indices and validation study for patients with diffuse large B-cell lymphoma in the rituximab era

Abstract

In diffuse large B-cell lymphoma (DLBCL), patients needing new alternative regimens in first-line treatment should be selected with better risk classification. After International Prognostic Index (IPI), Revised-IPI (R-IPI), National Comprehensive Cancer Network (NCCN)-IPI, and Grupo Español de Linfomas y Trasplante Autólogo de Médula Ósea (GELTAMO)-IPI, have been developed to im-prove risk predictions. This study compared performances of four prognostic indices concerning differentiation of overall survival (OS), the most critical endpoint. The study was conducted on 116 patients diagnosed with DLBCL. Patients with primary nervous system and testicular DLBCL, and post-transplant lymphoproliferative disorders, were excluded. The fitting of prognostic indices for database and the prediction of patient discrimination were compared using Akaike’s information criterion and concordance index. Of the study cohort, 63.8% were male, the median age was 56 (18-88), and median follow-up term was 45.6 (0.3-75.2) months. All fac-tors, constituting IPI and R-IPI scores, demonstrated a significant difference in OS. Involvements of the extranodal regions specified in NCCN-IPI and elevated serum beta-2 microglobulin levels in GELTAMO-IPI had prognostic significance (p= 0.005 and p= 0.040, respectively). Each of the four prognostic indices, resulted in risk groups with significantly different OS. R-IPI provided the best fit for database, while NCCN-IPI provided the best discrimination between patients with high and low OS. Although NCCN-IPI provides the best discrimination between patients with short and long OS, using original IPI still seems acceptable in the rituximab era. Integration of tumor molecular characteristics into NCCN-IPI may better characterize high-risk group in new treatment approaches.